The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the ...The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the TR hazard severity of LIBs,are not known.In this paper,the TR and gas venting behavior of three 100 A h lithium iron phosphate(LFP)batteries with different safety valves are investigated under overheating.Compared to previous studies,the main contribution of this work is in studying and evaluating the effect of gas venting behavior and TR hazard severity of LFP batteries with three safety valve types.Two significant results are obtained:(Ⅰ)the safety valve type dominates over gas venting pressure of battery during safety venting,the maximum gas venting pressure of LFP batteries with a round safety valve is 3320 Pa,which is one order of magnitude higher than other batteries with oval or cavity safety valve;(Ⅱ)the LFP battery with oval safety valve has the lowest TR hazard as shown by the TR hazard assessment model based on gray-fuzzy analytic hierarchy process.This study reveals the effect of safety valve type on TR and gas venting,providing a clear direction for the safety valve design.展开更多
Li metal batteries are supposed to reach real application in order to fulfill the high-energy density requirement of energy storage system.Unfortunately,the commonly used carbonate electrolyte react with pristine Li,w...Li metal batteries are supposed to reach real application in order to fulfill the high-energy density requirement of energy storage system.Unfortunately,the commonly used carbonate electrolyte react with pristine Li,which result in short lifetime of lithium metal battery.To alleviate the side reactions of Li metal with liquid electrolyte,here we propose a phosphate rich polymer-inorganic layer as an interphase.Due to the inert properties of lithium phosphate derived from LiPO_(2)F_(2)and poly-ether,the side-reaction of carbonate solvent are prevented.As a result,lithium metal anode sustains for 800 cycles in symmetrical cell test under 1 m A cm^(-2).Even under strict condition(20μm Li,capacity ratio N/P=2.3,electrolyte/active material=3μL mg^(-1)),coin cell test still runs stable for 150 cycles with high Coulombic efficiency.Furthermore,both LiFePO_(4)and LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)pouch cell under 5μL m A^(-1)h^(-1)condition also exhibit good stability at 0.5 C and 2 C rate.With this approach,high-energy and high-power Li metal batteries are approaching to real application in the near future.展开更多
The worldwide proliferation of portable electronics has resulted in a dramatic increase in the number of spent lithium-ion batteries(LIBs).However,traditional recycling methods still have limitations because of such h...The worldwide proliferation of portable electronics has resulted in a dramatic increase in the number of spent lithium-ion batteries(LIBs).However,traditional recycling methods still have limitations because of such huge amounts of spent LIBs.Therefore,we proposed an ecofriendly and sustainable double recycling strategy to concurrently reuse the cathode(LiCoO_(2))and anode(graphite)materials of spent LIBs and recycled LiCoPO_(4)/graphite(RLCPG)in Li^(+)/PF^(-)_(6) co-de/intercalation dual-ion batteries.The recycle-derived dualion batteries of Li/RLCPG show impressive electrochemical performance,with an appropriate discharge capacity of 86.2 mAh·g^(-1) at25 mA·g^(-1) and 69%capacity retention after 400 cycles.Dual recycling of the cathode and anode from spent LIBs avoids wastage of resources and yields cathode materials with excellent performance,thereby offering an ecofriendly and sustainable way to design novel secondary batteries.展开更多
LiCoPO4 micron-rods with an average diameter of about 500 nm and length of about 5 μm were synthesized by dispersant-aided hydrothermal method. Poly(n-vinylpyrrolidone) (PVP) was used as dispersant in the hydrotherma...LiCoPO4 micron-rods with an average diameter of about 500 nm and length of about 5 μm were synthesized by dispersant-aided hydrothermal method. Poly(n-vinylpyrrolidone) (PVP) was used as dispersant in the hydrothermal method. The starting solution and the concentration of dispersant have significant influences on the morphology of LiCoPO4,and the electrochemical performance is improved via controlling the particle size and morphology by the hydrothermal method. The cell using smaller particle LiCoPO4 as cat...展开更多
The recycling of spent LiFePO_(4)batteries has received extensive attention due to its environmental impact and economic benefit.In the pretreatment process of spent LiFePO_(4)batteries,the separation of active materi...The recycling of spent LiFePO_(4)batteries has received extensive attention due to its environmental impact and economic benefit.In the pretreatment process of spent LiFePO_(4)batteries,the separation of active materials and current collectors determines the difficulty of the re-covery process and product quality.In this work,a facile and efficient pretreatment process is first proposed.After only freezing the electrode pieces and immersing them in boiling water,LiFePO_(4)materials were peeled from the Al foil.Then,after roasting under an inert atmosphere and sieving,all the cathode and anode active materials were easily and efficiently separated from the Al and Cu foils.The active materials were subjected to acid leaching,and the leaching solution was further used to prepare FePO_(4)and Li_(2)CO_(3).Finally,the battery-grade FePO_(4)and Li_(2)CO_(3)were used to re-synthesize LiFePO_(4)/C via the carbon thermal reduction method.The discharge capacities of re-synthesized LiFePO_(4)/C cathode were 144.2,139.0,133.2,125.5,and 110.5 mA·h·g−1 at rates of 0.1,0.5,1,2,and 5 C,which satisfies the requirement for middle-end LiFePO_(4)batteries.The whole process is environmental and has great potential for industrial-scale recycling of spent lithium-ion batteries.展开更多
La-doped Li3V2-xLax(PO4)3 ( x = 0.01, 0.02, and 0.03) cathode materials for lithium ion batteries were synthesized by the microwave-assisted carbothermal reduction method (MW-CTR). The structures and properties ...La-doped Li3V2-xLax(PO4)3 ( x = 0.01, 0.02, and 0.03) cathode materials for lithium ion batteries were synthesized by the microwave-assisted carbothermal reduction method (MW-CTR). The structures and properties of the prepared samples were investigated by X-ray diffraction (XRD) and electrochemical measurements. The results showed that all the three Li3V2-xLax(PO4)3 samples had the same monocfinic structures and sharper diffraction peaks of the crystal plane compared with those of the undoped Li3V2(PO4)3. The initial charge/discharge specific capacity, coulomb efficiency, and discharge decay rate of all the three Li3V2-xLax(PO4)3 samples were superior to those of the undoped Li3V2(PO4)3 sample, and the Li3V1.98La0.02(PO4)3 sample exhibited the best features among the three La-doped Li3V2-xLax(PO4)3 samples. Electrochemical impedance spectroscopy (EIS) demonstrated that the Li3V1.98Lao.02(PO4)3 sample had a lower charge transfer resistance and a higher Li ion diffusion coefficient compared with the undoped Li3V2 (PO4)3 sample.展开更多
This mini-review highlights selectively the recent research progress in the composites of Li Fe PO4 and graphene. In particularly, the different fabrication protocols, and the electrochemical performance of the compos...This mini-review highlights selectively the recent research progress in the composites of Li Fe PO4 and graphene. In particularly, the different fabrication protocols, and the electrochemical performance of the composites are summarized in detail. The structural and morphology characters of graphene sheets that may affect the property of the composites are discussed briefly. The possible ongoing researches in area are speculated upon.展开更多
Well-shaped and uniformly dispersed LiFePOnanorods with a length of 400–500 nm and a diameter of about 100 nm, are obtained with participation of a proper amount of anion surfactant sodium dodecyl sulfonate(SDS) wi...Well-shaped and uniformly dispersed LiFePOnanorods with a length of 400–500 nm and a diameter of about 100 nm, are obtained with participation of a proper amount of anion surfactant sodium dodecyl sulfonate(SDS) without any further heating as a post-treatment. The surfactant acts as a self-assembling supermolecular template, which stimulated the crystallization of LiFePOand directed the nanoparticles growing into nanorods between bilayers of surfactant(BOS). LiFePOnanorods with the reducing crystal size along the b axis shorten the diffusion distance of Liextraction/insertion, and thus improve the electrochemical properties of LiFePOnanorods. Such prepared LiFePOnanorods exhibited excellent specific capacity and high rate capability with discharge capacity of 151 mAh/g, 122 mAh/g and 95 mAh/g at 0.1C, 1 C and 5 C, respectively. Such excellent performance of LiFePOnanorods is supposed to be ascribed to the fast Lidiffusion velocity from reduced crystal size along the b axis and the well electrochemical conductivity. The structure, morphology and electrochemical performance of the samples were characterized by XRD, FE-SEM, HRTEM, charge/discharge tests, and EIS(electrochemical impedance spectra).展开更多
Amorphous carbon and graphene co-modified LiFePO4 nanocomposite has been synthesized via a facile polyol process in connection with a following thermal treatment.Various characterization techniques,including XRD.Mossb...Amorphous carbon and graphene co-modified LiFePO4 nanocomposite has been synthesized via a facile polyol process in connection with a following thermal treatment.Various characterization techniques,including XRD.Mossbauer spectra,Raman spectra,SEM,TEM,BET,O2-TPO,galvano charge-discharge,CV and EIS were applied to investigate the phase composition,carbon content,morphological structure and electrochemical performance of the synthesized samples.The effect of introducing way of carbon sources on the properties and performance of LiFePO4/C/graphene composite was paid special attention.Under optimized synthetic conditions,highly crystalized olivine-type LiFePO4was successfully obtained with electron conductive Fe2P and FeP as the main impurity phases.SEM and TEM analyses demonstrated the graphene sheets were randomly distributed inside the sample to create an open structured LiFePO4 with respect to graphene,while the glucosederived carbon mainly coated over LiFeP04 particles which effectively connected the graphene sheets and LiFePO4 particles to result in a more efficient charge transfer process.As a result,favorable electrochemical performance was achieved.The performance of the amorphous carbon-graphene co-modified LiFePO4 was further progressively improved upon cycling in the first 200 cycles to reach a reversible specificcapacity as high as 97 mAh·g-1 at 10 C rate.展开更多
Lithium-iron manganese phosphates(LiFex Mn_(1-x)PO_(4),0.1<x<0.9)have the merits of high safety and high working voltage.However,they also face the challenges of insufficient conductivity and poor cycling stabil...Lithium-iron manganese phosphates(LiFex Mn_(1-x)PO_(4),0.1<x<0.9)have the merits of high safety and high working voltage.However,they also face the challenges of insufficient conductivity and poor cycling stability.Some progress has been achieved to solve these problems.Herein,we firstly summarized the influence of different electrolyte systems on the electrochemical performance of LiFexMn_(1-x)PO_(4),and then discussed the effect of element doping,lastly studied the influences of conductive layer coating and morphology control on the cycling stability.Finally,the prospects and challenges of developing high-cycling LiFexMn_(1-x)PO_(4) were proposed.展开更多
Since lithium iron phosphate cathode material does not contain high-value metals other than lithium,it is therefore necessary to strike a balance between recovery efficiency and economic benefits in the recycling of w...Since lithium iron phosphate cathode material does not contain high-value metals other than lithium,it is therefore necessary to strike a balance between recovery efficiency and economic benefits in the recycling of waste lithium iron phosphate cathode materials.Here,we describe a selective recovery process that can achieve economically efficient recovery and an acceptable lithium leaching yield.Adjusting the acid concentration and amount of oxidant enables selective recovery of lithium ions.Iron is retained in the leaching residue as iron phosphate,which is easy to recycle.The effects of factors such as acid concentration,acid dosage,amount of oxidant,and reaction temperature on the leaching of lithium and iron are comprehensively explored,and the mechanism of selective leaching is clarified.This process greatly reduces the cost of processing equipment and chemicals.This increases the potential industrial use of this process and enables the green and efficient recycling of waste lithium iron phosphate cathode materials in the future.展开更多
Surface deterioration occurs more easily in nickel-rich cathode materials with the increase of nickel content.To simultaneously pre-vent deterioration of active cathode materials and improve the electrochemical perfor...Surface deterioration occurs more easily in nickel-rich cathode materials with the increase of nickel content.To simultaneously pre-vent deterioration of active cathode materials and improve the electrochemical performance of the nickel-rich cathode material,the surface of nickel-rich LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode material is decorated with the stable structure and conductive Li_(3)PO_(4)by a facile method.The LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)-1wt%,2wt%,3wt%Li_(3)PO_(4)samples deliver a high-capacity retention of more than 85%after 100 cycles at 1 C under a high voltage of 4.5 V.The effect of different coating amounts(0-5wt%)for the LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode is analyzed in detail.Results show that 2wt%coating of Li_(3)PO_(4)gives better performance compared to other coating concentrations.Detailed analysis of the structure of the samples during the charge−discharge process is performed by in-situ X-ray diffraction.It is indicated that the modification for LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode could protect the well-layered structure under high voltages.In consequence,the electrochemical performance of modified samples is greatly improved.展开更多
Lithium iron phosphate (LiFePO4) doped with magnesium was hydrothermally synthesized from commercial LiOH, FeSO4, H3PO4 and MgSO4 with glucose as carbon precursor in aqueous solution. The samples were characterized ...Lithium iron phosphate (LiFePO4) doped with magnesium was hydrothermally synthesized from commercial LiOH, FeSO4, H3PO4 and MgSO4 with glucose as carbon precursor in aqueous solution. The samples were characterized by X-ray powder diffraction, scanning electron microscopy and constant charge-discharge cycling. The results show that the synthesized powders have been in situ coated with carbon precursor produced from caramel reaction of glucose. At ambient temperature (28±2℃), the electrochemical performances of LiFePO4 prepared exhibit the high discharge capacity of 135 mAh g^-1 at 5C and good capacity retention of 98% over 90 cycles. The excellent electrochemical performances should be correlated with the intimate contact between carbon and LiFePO4 primary and secondary particles, resulting from the in situ formation of carbon precursor/carbon, leading to the increase in conductivity of LiFePO4.展开更多
Olivine LiFePO4/C composite cathode materials were synthesized by a solid state method in N2 + 5vol% H2 atmosphere. The effects of different iron sources, including Fe(OH)3 and FeC2O4·2H2O, on the performance ...Olivine LiFePO4/C composite cathode materials were synthesized by a solid state method in N2 + 5vol% H2 atmosphere. The effects of different iron sources, including Fe(OH)3 and FeC2O4·2H2O, on the performance of as-synthesized cathode materials were investigated and the causes were also analyzed. The crystal structure, the morphology, and the electrochemical performance of the prepared samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), laser particle-size distribution measurement, and other electrochemical techniques. The results demonstrate that the LiFePO4/C materials obtained from Fe(OH)3 at 800℃ and FeC2O4·2H2O at 700℃ have the similar electrochemical performances. The initial discharge capacities of LiFePO4/C synthesized from Fe(OH)3 and FeC2O4·2H2O are 134.5 mAh.g^-1 and 137.4 mAh.g^-1 at the C/5 rate, respectively. How- ever, the tap density of the LiFePO4/C materials obtained from Fe(OH)3 are higher, which is significant for the improvement of the capacity of the battery.展开更多
Olivine-structured pure LIFePO4 and doped LI(M, Fe)PO4 (M=La, Ce, Nd, Mn, Co, Ni) have been synthesized by a solvothermal method. X-ray diffraction and field emission scanning electron microscopy analyses indicate...Olivine-structured pure LIFePO4 and doped LI(M, Fe)PO4 (M=La, Ce, Nd, Mn, Co, Ni) have been synthesized by a solvothermal method. X-ray diffraction and field emission scanning electron microscopy analyses indicate that the as-prepared LiFePO4 is well-crystallized nanopowders without any detectable impurity phases. The electronic conductivity of LiFePO4 is enhanced by around 1-3 orders by doping. It was found that doping alone is not sufficient for the high-rate performance of LiFePO4 and surface coating with such as carbon should be needed. The best dopant for LiFePO4 is Nd among those studied in the present work. Accordingly, doping with 1 mol fraction Nd leads to an increase in 70 mAh/g at 0.1 C for the hydrothermally synthesized sample and 50 mAh/g at 1.0 C after carbon-coating in comparison with the undoped samples.展开更多
Lithium iron phosphate coated with carbon (LiFePO4/C) was synthesized by improved solid-state reaction using comparatively lower temperature and fewer sintering time. The carbon came from citric acid, which acted as...Lithium iron phosphate coated with carbon (LiFePO4/C) was synthesized by improved solid-state reaction using comparatively lower temperature and fewer sintering time. The carbon came from citric acid, which acted as a new carbon source. It was characterized by thermogravimetry and differential thermal analysis (TG/DTA), X ray diffractometer (XRD), Element Analysis (EA) and Scanning electron microscope (SEM). We also studied the electrochemical properties of the material. The first discharge capacity of the LiFePO4/C is 121 mAh·g^-1 at 10 mA·g^-1 at room temperature. When the current density increased to 100 mA·g^-1, the first discharge capacity decreased to 110 mAh·g^-1 and retained 95% of the initial capacity after 100 cycles. The LiFePO4/C obtained shows a good electrochemical capacity and cycle ability at a large current density.展开更多
Due to the large error of the traditional battery theoretical model during large-rate discharge for electromagnetic launch,the Shepherd derivative model considering the factors of the pulse cycle condition,temperature...Due to the large error of the traditional battery theoretical model during large-rate discharge for electromagnetic launch,the Shepherd derivative model considering the factors of the pulse cycle condition,temperature,and life is proposed by the Naval University of Engineering.The discharge rate of traditional lithium-ion batteries does not exceed 10C,while that for electromagnetic launch reaches 60C.The continuous pulse cycle condition of ultra-large discharging rate causes many unique electrochemical reactions inside the cells.The traditional model cannot accurately describe the discharge characteristics of the battery.The accurate battery theoretical model is an important basis for system efficiency calculation,precise discharge control,and remaining capacity prediction.To this purpose,an experimental platform for electromagnetic launch is built,and discharge characteristics of the battery under different rate,temperature,and life decay are measured.Through the experimental test and analysis,the reason that the traditional model cannot accurately characterize the large-rate discharge process is analyzed.And a novel battery theoretical model is designed with the help of genetic algorithm,which is integrated with the electromagnetic launch topology.Numerical simulation is compared with the experimental results,which verifies the modeling accuracy for the large-rate discharge.On this basis,a variety of discharge conditions are applied to test the applicability of the model,resulting in better results.Finally,with the continuous cycle-pulse condition in the electromagnetic launch system,the stability and accuracy of the model are confirmed.展开更多
LiFePO_(4),one of the mainstream cathode materials of current EV batteries,exhibits experimental diffusion coefficients(D_(c))of Li^(+)which are not only several orders of magnitude lower than those predicted by the i...LiFePO_(4),one of the mainstream cathode materials of current EV batteries,exhibits experimental diffusion coefficients(D_(c))of Li^(+)which are not only several orders of magnitude lower than those predicted by the ionic hopping barriers obtained from theoretical calculations and spectroscopic measurements,but also span several orders from 10^(-14)to 10^(-18)cm^(2)s^(-1)under different states of charge(SOC)and the charging rates(C-rates).Atomic level understanding of such sluggishness and diversity of Li^(+)transport kinetics would be of significance in improving the rate performance of LiFePO_(4)through material and operation optimization but remain challenging.Herein,we show that the high sensitivity of Li^(+)hopping barriers on the local Li–Li coordination environments(numbers and configurations)plays a key role in the ion transport kinetics.This is due a neural network-based deep potential(DP)which allows accurate and efficient calculation of hopping barriers of Li^(+)in LiFePO_(4)with various Li–Li coordination environments,with which the kinetic Monte-Carlo(KMC)method was employed to determine the D_(c)values at various C-rates and SOC across a broad spectrum.Especially,an accelerated KMC simulation strategy is proposed to obtain the D_(c)values under a wide range of SOC at low C-rates,which agree well with that obtained from the galvanostatic intermittent titration technique(GITT).The present study provides accurate descriptions of Li^(+)transport kinetics at both very high and low C-rates,which remains challenging to experiments and first-principles calculations,respectively.Finally,it is revealed that the gradient distributions of Li^(+)density along the diffusion path result in great asymmetry in the barriers of the forward and backward hopping,causing very slow diffusion of Li^(+)and the diverse variation of D_(c).展开更多
The flourishing expansion of the lithium-ion batteries(LIBs) market has led to a surge in the demand for lithium resources. Developing efficient recycling technologies for imminent large-scale retired LIBs can signifi...The flourishing expansion of the lithium-ion batteries(LIBs) market has led to a surge in the demand for lithium resources. Developing efficient recycling technologies for imminent large-scale retired LIBs can significantly facilitate the sustainable utilization of lithium resources. Here, we successfully extract active lithium from spent LIBs through a simple, efficient, and low-energy-consumption chemical leaching process at room temperature, using a solution comprised of polycyclic aromatic hydrocarbons and ether solvents. The mechanism of lithium extraction is elucidated by clarifying the relationship between the redox potential and extraction efficiency. More importantly, the reclaimed active lithium is directly employed to fabricate LiFePO_(4) cathode with performance comparable to commercial materials. When implemented in 56 Ah prismatic cells, the cells deliver stable cycling properties with a capacity retention of ~90% after 1200 cycles. Compared with the other strategies, this technical approach shows superior economic benefits and practical promise. It is anticipated that this method may redefine the recycling paradigm for retired LIBs and drive the sustainable development of industries.展开更多
A LiFeP04-type lithium secondary battery cell of 8 Ah capacity with a high energy density and power density was developed for hybrid electric vehicle(HEV)applications by optimizing the key raw materials and process de...A LiFeP04-type lithium secondary battery cell of 8 Ah capacity with a high energy density and power density was developed for hybrid electric vehicle(HEV)applications by optimizing the key raw materials and process design.The 8 Ah class LiFePO_(4)cell with an energy density of 77.2 Wh·kg^(-1)exhibits a power density of 2818 W·kg^(-1)at 50%SOC(state of charge).The battery shows good cyclic capability with the capacity retention of 81.1%after 1,870 cycles at 5 C charge and 10 C discharge rates.It is demonstrated that the cells have an excellent balance of high-power,high-energy,low temperature,and long-life performance for meeting the requirements of HEV.展开更多
基金supported by the National Key R&D Program of China(No.2021YFB2402001)the Postgraduate Innovation and Entrepreneurship Practice Project of Anhui Province(No.2022cxcysj013)+2 种基金the China Postdoctoral Science Foundation(No.2022T150615)the Fundamental Research Funds for the Central Universities(No.WK5290000002)supported by Youth Innovation Promotion Association CAS(No.Y201768)。
文摘The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the TR hazard severity of LIBs,are not known.In this paper,the TR and gas venting behavior of three 100 A h lithium iron phosphate(LFP)batteries with different safety valves are investigated under overheating.Compared to previous studies,the main contribution of this work is in studying and evaluating the effect of gas venting behavior and TR hazard severity of LFP batteries with three safety valve types.Two significant results are obtained:(Ⅰ)the safety valve type dominates over gas venting pressure of battery during safety venting,the maximum gas venting pressure of LFP batteries with a round safety valve is 3320 Pa,which is one order of magnitude higher than other batteries with oval or cavity safety valve;(Ⅱ)the LFP battery with oval safety valve has the lowest TR hazard as shown by the TR hazard assessment model based on gray-fuzzy analytic hierarchy process.This study reveals the effect of safety valve type on TR and gas venting,providing a clear direction for the safety valve design.
基金supported by the Jilin Province Science and Technology Department Program(Nos.YDZJ202201ZYTS304)the Science and Technology Project of Jilin Provincial Education Department(JJKH20220428KJ)+3 种基金the R&D Program of Power Batteries with Low Temperature and High Energy,Science and Technology Bureau of Changchun(19SS013)the Key Subject Construction of Physical Chemistry of Northeast Normal Universitythe Fundamental Research Funds for the Central Universities(2412020FZ007,2412020FZ008)the National Natural Science Foundation of China(22102020)。
文摘Li metal batteries are supposed to reach real application in order to fulfill the high-energy density requirement of energy storage system.Unfortunately,the commonly used carbonate electrolyte react with pristine Li,which result in short lifetime of lithium metal battery.To alleviate the side reactions of Li metal with liquid electrolyte,here we propose a phosphate rich polymer-inorganic layer as an interphase.Due to the inert properties of lithium phosphate derived from LiPO_(2)F_(2)and poly-ether,the side-reaction of carbonate solvent are prevented.As a result,lithium metal anode sustains for 800 cycles in symmetrical cell test under 1 m A cm^(-2).Even under strict condition(20μm Li,capacity ratio N/P=2.3,electrolyte/active material=3μL mg^(-1)),coin cell test still runs stable for 150 cycles with high Coulombic efficiency.Furthermore,both LiFePO_(4)and LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)pouch cell under 5μL m A^(-1)h^(-1)condition also exhibit good stability at 0.5 C and 2 C rate.With this approach,high-energy and high-power Li metal batteries are approaching to real application in the near future.
基金the National Natural Science Foundation of China(No.52173246)the Science and Technology Planning Project of Guangzhou City,China(No.2023B03J1278)。
文摘The worldwide proliferation of portable electronics has resulted in a dramatic increase in the number of spent lithium-ion batteries(LIBs).However,traditional recycling methods still have limitations because of such huge amounts of spent LIBs.Therefore,we proposed an ecofriendly and sustainable double recycling strategy to concurrently reuse the cathode(LiCoO_(2))and anode(graphite)materials of spent LIBs and recycled LiCoPO_(4)/graphite(RLCPG)in Li^(+)/PF^(-)_(6) co-de/intercalation dual-ion batteries.The recycle-derived dualion batteries of Li/RLCPG show impressive electrochemical performance,with an appropriate discharge capacity of 86.2 mAh·g^(-1) at25 mA·g^(-1) and 69%capacity retention after 400 cycles.Dual recycling of the cathode and anode from spent LIBs avoids wastage of resources and yields cathode materials with excellent performance,thereby offering an ecofriendly and sustainable way to design novel secondary batteries.
文摘LiCoPO4 micron-rods with an average diameter of about 500 nm and length of about 5 μm were synthesized by dispersant-aided hydrothermal method. Poly(n-vinylpyrrolidone) (PVP) was used as dispersant in the hydrothermal method. The starting solution and the concentration of dispersant have significant influences on the morphology of LiCoPO4,and the electrochemical performance is improved via controlling the particle size and morphology by the hydrothermal method. The cell using smaller particle LiCoPO4 as cat...
基金This work was financially supported by the Key-Area Research and Development Program of Guangdong Province,China(No.2020B090919003)the National Natural Science Foundation of China(Nos.51834008,51874040,and U1802253)the Fundamental Research Funds for the Central Universities(No.FRF-TP-18-020A3).
文摘The recycling of spent LiFePO_(4)batteries has received extensive attention due to its environmental impact and economic benefit.In the pretreatment process of spent LiFePO_(4)batteries,the separation of active materials and current collectors determines the difficulty of the re-covery process and product quality.In this work,a facile and efficient pretreatment process is first proposed.After only freezing the electrode pieces and immersing them in boiling water,LiFePO_(4)materials were peeled from the Al foil.Then,after roasting under an inert atmosphere and sieving,all the cathode and anode active materials were easily and efficiently separated from the Al and Cu foils.The active materials were subjected to acid leaching,and the leaching solution was further used to prepare FePO_(4)and Li_(2)CO_(3).Finally,the battery-grade FePO_(4)and Li_(2)CO_(3)were used to re-synthesize LiFePO_(4)/C via the carbon thermal reduction method.The discharge capacities of re-synthesized LiFePO_(4)/C cathode were 144.2,139.0,133.2,125.5,and 110.5 mA·h·g−1 at rates of 0.1,0.5,1,2,and 5 C,which satisfies the requirement for middle-end LiFePO_(4)batteries.The whole process is environmental and has great potential for industrial-scale recycling of spent lithium-ion batteries.
基金supported by the Key Research Project of the Science and Technology Department of Jiangxi Province,China (2006)
文摘La-doped Li3V2-xLax(PO4)3 ( x = 0.01, 0.02, and 0.03) cathode materials for lithium ion batteries were synthesized by the microwave-assisted carbothermal reduction method (MW-CTR). The structures and properties of the prepared samples were investigated by X-ray diffraction (XRD) and electrochemical measurements. The results showed that all the three Li3V2-xLax(PO4)3 samples had the same monocfinic structures and sharper diffraction peaks of the crystal plane compared with those of the undoped Li3V2(PO4)3. The initial charge/discharge specific capacity, coulomb efficiency, and discharge decay rate of all the three Li3V2-xLax(PO4)3 samples were superior to those of the undoped Li3V2(PO4)3 sample, and the Li3V1.98La0.02(PO4)3 sample exhibited the best features among the three La-doped Li3V2-xLax(PO4)3 samples. Electrochemical impedance spectroscopy (EIS) demonstrated that the Li3V1.98Lao.02(PO4)3 sample had a lower charge transfer resistance and a higher Li ion diffusion coefficient compared with the undoped Li3V2 (PO4)3 sample.
基金the Science and Technology Commission of Shanghai Municipality (No. 12nm0503500)the National Science Foundation of China (Nos. 21376148, 11374205)
文摘This mini-review highlights selectively the recent research progress in the composites of Li Fe PO4 and graphene. In particularly, the different fabrication protocols, and the electrochemical performance of the composites are summarized in detail. The structural and morphology characters of graphene sheets that may affect the property of the composites are discussed briefly. The possible ongoing researches in area are speculated upon.
基金financially sponsored by the National Natural Science Foundation of China(Grant No:91534205)
文摘Well-shaped and uniformly dispersed LiFePOnanorods with a length of 400–500 nm and a diameter of about 100 nm, are obtained with participation of a proper amount of anion surfactant sodium dodecyl sulfonate(SDS) without any further heating as a post-treatment. The surfactant acts as a self-assembling supermolecular template, which stimulated the crystallization of LiFePOand directed the nanoparticles growing into nanorods between bilayers of surfactant(BOS). LiFePOnanorods with the reducing crystal size along the b axis shorten the diffusion distance of Liextraction/insertion, and thus improve the electrochemical properties of LiFePOnanorods. Such prepared LiFePOnanorods exhibited excellent specific capacity and high rate capability with discharge capacity of 151 mAh/g, 122 mAh/g and 95 mAh/g at 0.1C, 1 C and 5 C, respectively. Such excellent performance of LiFePOnanorods is supposed to be ascribed to the fast Lidiffusion velocity from reduced crystal size along the b axis and the well electrochemical conductivity. The structure, morphology and electrochemical performance of the samples were characterized by XRD, FE-SEM, HRTEM, charge/discharge tests, and EIS(electrochemical impedance spectra).
基金supported by the National Science Foundation for Distinguished Young Scholars of China(No.51025209)the National Nature Science Foundation of China(No.21103089)the Key Projects in Nature Science Foundation of Jiangsu Province(No.BK2011030)
文摘Amorphous carbon and graphene co-modified LiFePO4 nanocomposite has been synthesized via a facile polyol process in connection with a following thermal treatment.Various characterization techniques,including XRD.Mossbauer spectra,Raman spectra,SEM,TEM,BET,O2-TPO,galvano charge-discharge,CV and EIS were applied to investigate the phase composition,carbon content,morphological structure and electrochemical performance of the synthesized samples.The effect of introducing way of carbon sources on the properties and performance of LiFePO4/C/graphene composite was paid special attention.Under optimized synthetic conditions,highly crystalized olivine-type LiFePO4was successfully obtained with electron conductive Fe2P and FeP as the main impurity phases.SEM and TEM analyses demonstrated the graphene sheets were randomly distributed inside the sample to create an open structured LiFePO4 with respect to graphene,while the glucosederived carbon mainly coated over LiFeP04 particles which effectively connected the graphene sheets and LiFePO4 particles to result in a more efficient charge transfer process.As a result,favorable electrochemical performance was achieved.The performance of the amorphous carbon-graphene co-modified LiFePO4 was further progressively improved upon cycling in the first 200 cycles to reach a reversible specificcapacity as high as 97 mAh·g-1 at 10 C rate.
基金financially supported by the National Natural Science Foundation of China(Nos.51971090 and U21A20311)。
文摘Lithium-iron manganese phosphates(LiFex Mn_(1-x)PO_(4),0.1<x<0.9)have the merits of high safety and high working voltage.However,they also face the challenges of insufficient conductivity and poor cycling stability.Some progress has been achieved to solve these problems.Herein,we firstly summarized the influence of different electrolyte systems on the electrochemical performance of LiFexMn_(1-x)PO_(4),and then discussed the effect of element doping,lastly studied the influences of conductive layer coating and morphology control on the cycling stability.Finally,the prospects and challenges of developing high-cycling LiFexMn_(1-x)PO_(4) were proposed.
基金supported by the National Natural Science Foundation of China(Grant Nos.22125802,and 22078010)Beijing Natural Science Foundation(Grant No.2222017)Big Science Project from BUCT(Grant No.XK180301)。
文摘Since lithium iron phosphate cathode material does not contain high-value metals other than lithium,it is therefore necessary to strike a balance between recovery efficiency and economic benefits in the recycling of waste lithium iron phosphate cathode materials.Here,we describe a selective recovery process that can achieve economically efficient recovery and an acceptable lithium leaching yield.Adjusting the acid concentration and amount of oxidant enables selective recovery of lithium ions.Iron is retained in the leaching residue as iron phosphate,which is easy to recycle.The effects of factors such as acid concentration,acid dosage,amount of oxidant,and reaction temperature on the leaching of lithium and iron are comprehensively explored,and the mechanism of selective leaching is clarified.This process greatly reduces the cost of processing equipment and chemicals.This increases the potential industrial use of this process and enables the green and efficient recycling of waste lithium iron phosphate cathode materials in the future.
基金This work was financially supported by the Guangdong Key Laboratory of Battery Safety(No.2019B121203008)the National Natural Science Foundation of China(No.52072036),NSAF(No.U1930113)+2 种基金the Beijing Natural Science Foundation(No.L182022)the 13th Five-Year Plan of Advance Research and Sharing Techniques by Equipment Department(No.41421040202)the China Postdoctoral Science Foundation(No.2021TQ0034).
文摘Surface deterioration occurs more easily in nickel-rich cathode materials with the increase of nickel content.To simultaneously pre-vent deterioration of active cathode materials and improve the electrochemical performance of the nickel-rich cathode material,the surface of nickel-rich LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode material is decorated with the stable structure and conductive Li_(3)PO_(4)by a facile method.The LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)-1wt%,2wt%,3wt%Li_(3)PO_(4)samples deliver a high-capacity retention of more than 85%after 100 cycles at 1 C under a high voltage of 4.5 V.The effect of different coating amounts(0-5wt%)for the LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode is analyzed in detail.Results show that 2wt%coating of Li_(3)PO_(4)gives better performance compared to other coating concentrations.Detailed analysis of the structure of the samples during the charge−discharge process is performed by in-situ X-ray diffraction.It is indicated that the modification for LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode could protect the well-layered structure under high voltages.In consequence,the electrochemical performance of modified samples is greatly improved.
文摘Lithium iron phosphate (LiFePO4) doped with magnesium was hydrothermally synthesized from commercial LiOH, FeSO4, H3PO4 and MgSO4 with glucose as carbon precursor in aqueous solution. The samples were characterized by X-ray powder diffraction, scanning electron microscopy and constant charge-discharge cycling. The results show that the synthesized powders have been in situ coated with carbon precursor produced from caramel reaction of glucose. At ambient temperature (28±2℃), the electrochemical performances of LiFePO4 prepared exhibit the high discharge capacity of 135 mAh g^-1 at 5C and good capacity retention of 98% over 90 cycles. The excellent electrochemical performances should be correlated with the intimate contact between carbon and LiFePO4 primary and secondary particles, resulting from the in situ formation of carbon precursor/carbon, leading to the increase in conductivity of LiFePO4.
基金supported by the Science and Technology Research Item of Guangzhou, China (No.2007Z3-D0021)
文摘Olivine LiFePO4/C composite cathode materials were synthesized by a solid state method in N2 + 5vol% H2 atmosphere. The effects of different iron sources, including Fe(OH)3 and FeC2O4·2H2O, on the performance of as-synthesized cathode materials were investigated and the causes were also analyzed. The crystal structure, the morphology, and the electrochemical performance of the prepared samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), laser particle-size distribution measurement, and other electrochemical techniques. The results demonstrate that the LiFePO4/C materials obtained from Fe(OH)3 at 800℃ and FeC2O4·2H2O at 700℃ have the similar electrochemical performances. The initial discharge capacities of LiFePO4/C synthesized from Fe(OH)3 and FeC2O4·2H2O are 134.5 mAh.g^-1 and 137.4 mAh.g^-1 at the C/5 rate, respectively. How- ever, the tap density of the LiFePO4/C materials obtained from Fe(OH)3 are higher, which is significant for the improvement of the capacity of the battery.
基金supported by the Science-Technology Foundation of Zhejiang Province under grant No.2007C21100
文摘Olivine-structured pure LIFePO4 and doped LI(M, Fe)PO4 (M=La, Ce, Nd, Mn, Co, Ni) have been synthesized by a solvothermal method. X-ray diffraction and field emission scanning electron microscopy analyses indicate that the as-prepared LiFePO4 is well-crystallized nanopowders without any detectable impurity phases. The electronic conductivity of LiFePO4 is enhanced by around 1-3 orders by doping. It was found that doping alone is not sufficient for the high-rate performance of LiFePO4 and surface coating with such as carbon should be needed. The best dopant for LiFePO4 is Nd among those studied in the present work. Accordingly, doping with 1 mol fraction Nd leads to an increase in 70 mAh/g at 0.1 C for the hydrothermally synthesized sample and 50 mAh/g at 1.0 C after carbon-coating in comparison with the undoped samples.
文摘Lithium iron phosphate coated with carbon (LiFePO4/C) was synthesized by improved solid-state reaction using comparatively lower temperature and fewer sintering time. The carbon came from citric acid, which acted as a new carbon source. It was characterized by thermogravimetry and differential thermal analysis (TG/DTA), X ray diffractometer (XRD), Element Analysis (EA) and Scanning electron microscope (SEM). We also studied the electrochemical properties of the material. The first discharge capacity of the LiFePO4/C is 121 mAh·g^-1 at 10 mA·g^-1 at room temperature. When the current density increased to 100 mA·g^-1, the first discharge capacity decreased to 110 mAh·g^-1 and retained 95% of the initial capacity after 100 cycles. The LiFePO4/C obtained shows a good electrochemical capacity and cycle ability at a large current density.
基金This study was supported by the National Natural Science Foundation of China(Nos.51607187,51877214,51907203,51925704,and 52107235)the Hubei Provincial Natural Science Foundation of China(Nos.2019CFB371 and 2019CFB373)partially by No.12 Special Financial 349 Aid to China Postdoctoral Science Foundation(No.2019T120972).
文摘Due to the large error of the traditional battery theoretical model during large-rate discharge for electromagnetic launch,the Shepherd derivative model considering the factors of the pulse cycle condition,temperature,and life is proposed by the Naval University of Engineering.The discharge rate of traditional lithium-ion batteries does not exceed 10C,while that for electromagnetic launch reaches 60C.The continuous pulse cycle condition of ultra-large discharging rate causes many unique electrochemical reactions inside the cells.The traditional model cannot accurately describe the discharge characteristics of the battery.The accurate battery theoretical model is an important basis for system efficiency calculation,precise discharge control,and remaining capacity prediction.To this purpose,an experimental platform for electromagnetic launch is built,and discharge characteristics of the battery under different rate,temperature,and life decay are measured.Through the experimental test and analysis,the reason that the traditional model cannot accurately characterize the large-rate discharge process is analyzed.And a novel battery theoretical model is designed with the help of genetic algorithm,which is integrated with the electromagnetic launch topology.Numerical simulation is compared with the experimental results,which verifies the modeling accuracy for the large-rate discharge.On this basis,a variety of discharge conditions are applied to test the applicability of the model,resulting in better results.Finally,with the continuous cycle-pulse condition in the electromagnetic launch system,the stability and accuracy of the model are confirmed.
基金financially supported by the National Natural Science Foundation of China(22272122,21832004 and 21673163)。
文摘LiFePO_(4),one of the mainstream cathode materials of current EV batteries,exhibits experimental diffusion coefficients(D_(c))of Li^(+)which are not only several orders of magnitude lower than those predicted by the ionic hopping barriers obtained from theoretical calculations and spectroscopic measurements,but also span several orders from 10^(-14)to 10^(-18)cm^(2)s^(-1)under different states of charge(SOC)and the charging rates(C-rates).Atomic level understanding of such sluggishness and diversity of Li^(+)transport kinetics would be of significance in improving the rate performance of LiFePO_(4)through material and operation optimization but remain challenging.Herein,we show that the high sensitivity of Li^(+)hopping barriers on the local Li–Li coordination environments(numbers and configurations)plays a key role in the ion transport kinetics.This is due a neural network-based deep potential(DP)which allows accurate and efficient calculation of hopping barriers of Li^(+)in LiFePO_(4)with various Li–Li coordination environments,with which the kinetic Monte-Carlo(KMC)method was employed to determine the D_(c)values at various C-rates and SOC across a broad spectrum.Especially,an accelerated KMC simulation strategy is proposed to obtain the D_(c)values under a wide range of SOC at low C-rates,which agree well with that obtained from the galvanostatic intermittent titration technique(GITT).The present study provides accurate descriptions of Li^(+)transport kinetics at both very high and low C-rates,which remains challenging to experiments and first-principles calculations,respectively.Finally,it is revealed that the gradient distributions of Li^(+)density along the diffusion path result in great asymmetry in the barriers of the forward and backward hopping,causing very slow diffusion of Li^(+)and the diverse variation of D_(c).
基金supported by the National Key Research and Development Program of China (2022YFB2404800)the National Natural Science Foundation of China (U1966214 and 22008082)。
文摘The flourishing expansion of the lithium-ion batteries(LIBs) market has led to a surge in the demand for lithium resources. Developing efficient recycling technologies for imminent large-scale retired LIBs can significantly facilitate the sustainable utilization of lithium resources. Here, we successfully extract active lithium from spent LIBs through a simple, efficient, and low-energy-consumption chemical leaching process at room temperature, using a solution comprised of polycyclic aromatic hydrocarbons and ether solvents. The mechanism of lithium extraction is elucidated by clarifying the relationship between the redox potential and extraction efficiency. More importantly, the reclaimed active lithium is directly employed to fabricate LiFePO_(4) cathode with performance comparable to commercial materials. When implemented in 56 Ah prismatic cells, the cells deliver stable cycling properties with a capacity retention of ~90% after 1200 cycles. Compared with the other strategies, this technical approach shows superior economic benefits and practical promise. It is anticipated that this method may redefine the recycling paradigm for retired LIBs and drive the sustainable development of industries.
基金the State Basic Research Development Program of China(No.2009CB220100)the Ministry of Science and Technology(MOST)of China,US-China Collaboration on Cutting-Edge Technology Development of Electric Vehicles(No.2010DFA72760)+1 种基金the National Natural Science Foundation of China(Nos.50901009 and 51271029)the Fundamental Research Funds for the Central Universities(No.12QNJJ013)。
文摘A LiFeP04-type lithium secondary battery cell of 8 Ah capacity with a high energy density and power density was developed for hybrid electric vehicle(HEV)applications by optimizing the key raw materials and process design.The 8 Ah class LiFePO_(4)cell with an energy density of 77.2 Wh·kg^(-1)exhibits a power density of 2818 W·kg^(-1)at 50%SOC(state of charge).The battery shows good cyclic capability with the capacity retention of 81.1%after 1,870 cycles at 5 C charge and 10 C discharge rates.It is demonstrated that the cells have an excellent balance of high-power,high-energy,low temperature,and long-life performance for meeting the requirements of HEV.