Synthesis and Characterization of Li_(1.05)Co_(0.3)Ni_(0.35)Mn_(0.3)M_(0.05)O_2(M=Ge,Sn)Cathode Materials for Lithium Ion Battery

In order to improve the electrochemical performance and thermal stability of Li1.05Co1/3Nil/3Mnl/302 materials, Lil.05CO0.3 Ni0.35Mno.3Mo.0502（M=Ge,Sn） cathode materials were synthesized via co-precipitation method. The structure, electrochemical performance and thermal stability were characterized by X-ray diffraction（XRD）, charge/discharge cycling, cyclic voltammetry（CV）, electrochemical impedance spectroscopy（EIS） and differential scanning calorimetry（DSC）. ESEM showed that Sn-doped and Ge- doped slightly increased the size of grains. XRD and CV showed that Sn-doped and Ge-doped powders were homogeneous and had the better layered structure than the bare one. Sn-doped and Ge-doped improved high rate discharge capacity and cycle-life performance. The reason of the better cycling performance of the doped one was the increasing of lithium-ion diffusion rate and charge transfer rate. Sn-doped and Ge-doped also improved the mateials thermal stability.

Suppress oxygen evolution of lithium-rich manganese-based cathode materials via an integrated strategy

Improving the reversibility of anionic redox and inhibiting irreversible oxygen evolution are the main challenges in the application of high reversible capacity Li-rich Mn-based cathode materials.A facile synchronous lithiation strategy combining the advantages of yttrium doping and LiYO_(2) surface coating is proposed.Yttrium doping effectively suppresses the oxygen evolution during the delithiation process by increasing the energy barrier of oxygen evolution reaction through strong Y–O bond energy.LiYO_(2) nanocoating has the function of structural constraint and protection,that protecting the lattice oxygen exposed to the surface,thus avoiding irreversible oxidation.As an Li^(+) conductor,LiYO_(2) nano-coating can provide a fast Li^(+) transfer channel,which enables the sample to have excellent rate performance.The synergistic effect of Y doping and nano-LiYO_(2) coating integration suppresses the oxygen release from the surface,accelerates the diffusion of Li^(+)from electrolyte to electrode and decreases the interfacial side reactions,enabling the lithium ion batteries to obtain good electrochemical performance.The lithium-ion full cell employing the Y-1 sample(cathode)and commercial graphite(anode)exhibit an excellent specific energy density of 442.9 Wh kg^(-1) at a current density of 0.1C,with very stable safety performance,which can be used in a wide temperature range(60 to-15℃)stable operation.This result illustrates a new integration strategy for advanced cathode materials to achieve high specific energy density.

Smart materials for safe lithium-ion batteries against thermal runaway

In recent years,the new energy storage system,such as lithium ion batteries(LIBs),has attracted much attention.In order to meet the demand of industrial progress for longer cycle life,higher energy density and cost efficiency,a quantity of research has been conducted on the commercial application of LIBs.However,it is difficult to achieve satisfying safety and cycling performance simultaneously.There may be thermal runaway(TR),external impact,overcharge and overdischarge in the process of battery abuse,which makes the safety problem of LIBs more prominent.In this review,we summarize recent progress in the smart safety materials design towards the goal of preventing TR of LIBs reversibly from different abuse conditions.Benefiting from smart responsive materials and novel structural design,the safety of LIBs can be improved a lot.We expect to provide a comprehensive reference for the development of smart and safe lithium-based battery materials.

Two-Dimensional Graphitic Carbon-Nitride(g-C_(3)N_(4))-Coated LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)Cathodes for High-Energy-Density and Long-Life Lithium Batteries

High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance.Herein,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis method.As an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal cracking.Moreover,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode.As a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.

Degradation analysis and doping modification optimization for high-voltage P-type layered cathode in sodium-ion batteries

Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage applications.Despite this,a comprehensive understanding of the mechanisms underpinning their structural deterioration at elevated voltages remains insufficiently explored.In this study,we unveil a layer delamination phenomenon of Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2)(NNM)within the 2.0-4.3 V voltage,attributed to considerable volumetric fluctuations along the c-axis and lattice oxygen reactions induced by the simultaneous Ni^(3+)/Ni^(4+)and anion redox reactions.By introducing Mg doping to diminished Ni-O antibonding,the anion oxidation-reduction reactions are effectively mitigated,and the structural integrity of the P2 phase remains firmly intact,safeguarding active sites and precluding the formation of novel interfaces.The Na_(0.67)Mg_(0.05)Ni_(0.25)Mn_(0.7)O_(2)(NMNM-5)exhibits a specific capacity of100.7 mA h g^(-1),signifying an 83%improvement compared to the NNM material within the voltage of2.0-4.3 V.This investigation underscores the intricate interplay between high-voltage stability and structural degradation mechanisms in layered sodium-ion oxides.

Novel high-voltage cathode for aqueous zinc ion batteries:Porous K_(0.5)VOPO_(4)·1.5H_(2)O with reversible solid-solution intercalation and conversion storage mechanism

Cathode materials that possess high output voltage,as well as those that can be mass-produced using facile techniques,are crucial for the advancement of aqueous zinc-ion battery(ZIBs)applications,Herein,we present for the first time a new porous K_(0.5)VOPO_(4)·1.5H_(2)O polyanionic cathode(P-KIVP)with high output voltage(above 1.2 V)that can be manufactured at room temperature using straightforward coprecipitation and etching techniques.The P-KVP cathode experiences anisotropic crystal plane expansion via a sequential solid-solution intercalation and phase co nversion pathway throughout the Zn^(2+)storage process,as confirmed by in-situ synchrotron X-ray diffraction and ex-situ X-ray photoelectron spectroscopy.Similar to other layered vanadium-based polyanionic materials,the P-KVP cathode experiences a progressive decline in voltage during the cycle,which is demonstrated to be caused by the irreversible conversion into amorphous VO_(x).By introducing a new electrolyte containing Zn(OTF)_(2) to a mixed triethyl phosphate and water solution,it is possible to impede this irreversible conversion and obtain a high output voltage and longer cycle life by forming a P-rich cathode electrolyte interface layer.As a proof-of-concept,the flexible fiber-shaped ZIBs based on modified electrolyte woven into a fabric watch band can power an electronic watch,highlighting the application potential of P-KVP cathode.

Preparation and characterization of LiMn_(1.5)Me_(0.5)O_4 (Me=Ti,Fe,Ni,Zn) for lithium-ion battery cathode materials

Based on synthesizing pure spinel type lithium manganese oxides,the derivations such as LiMn1.5Ti0.5-O4,LiMn1.5Fe0.5O4,LiMn1 .5Ni0.5O4 and LiMn1.5Zn0.5O4 were prepared using solid- step-sintering method. The structures were characterized by using XRD,SEM and laser granulometer. The electrochemical measurement results show that the elemen t of iron or nickel can raise the discharging plateau voltage of LiMn2O4,an d element titanium improves the electrochemistry property of LiMn2O4 little,while element zinc destroys the electrochemistry property of LiMn2O4. The i nfluence of elements of titanium,iron,nickel,or zinc on the structure of LiMn 2O4 pure phase was discussed from the viewpoint of structural chemistry.

Influence of synthesis temperature on electrochemical performance of polyoxomolybdate as cathode material of lithium ion battery

In order to improve the electrochemical performance of polyoxomolybdate Na3[AlMo6O24H6]（NAM） as the cathode material of lithium ion battery, the NAM materials with small particle size were synthesized by elevatingthe synthesistemperaturein the solution.The as-prepared NAM materials were investigated by FT-IR, XRD, SEM and EIS. Their discharge-charge and cycle performance were also tested. The resultsshowthat the particle size decreasesto less than10μm at the temperature ofhigher than 40℃.When synthesized at 80℃,the NAMwiththe smallest particle size （-3μm）exhibitsthe best electrochemical performance such ashigh initial discharge capacity of 409 mA·h/gandcoulombic efficiency of 95% in the first cycle at 0.04C.

Preparation and electrochemical properties of Y-doped Li_3V_2(PO_4)_3 cathode materials for lithium batteries

Y-doped Li3V2（PO4）3 cathode materials were prepared by a carbothermal reduction（CTR） process.The properties of the Y-doped Li3V2（PO4）3 were investigated by X-ray diffraction（XRD） and electrochemical measurements.XRD studies showed that the Y-doped Li3V2（PO4）3 had the same monoclinic structure as the undoped Li3V2（PO4）3.The Y-doped Li3V2（PO4）3 samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram（CV）, and electrochemical impedance spectra（EIS）.The optimal doping content of Y was x=0.03 in Li3V2-xYx（PO4）3 system.The Y-doped Li3V2（PO4）3 samples showed a better cyclic ability.The electrode reaction reversibility was enhanced, and the charge transfer resistance was decreased through the Y-doping.The improved electrochemical perormances of the Y-doped Li3V2（PO4）3 cathode materials were attributed to the addition of Y3＋ ion by stabilizing the monoclinic structure.

Polyoxovanadate(NH_4)_7[MnV_(13)O_(38)] as cathode material for lithium ion battery and improved electrochemical performance

The polyoxovanadate（NH4）7[MnV13O38]（AMV） was synthesized and characterized by X-ray diffraction pattern, Fourier transform infrared spectra, and field emission scanning electron microscope equipped with energy dispersive X-ray spectroscopy. In order to improve the electrochemical performance of AMV, the particle size of as-prepared AMV is decreased to nanoscale by re-precipitation in the water-ethanol solution. The results of the electrochemical impedance spectra and the 4-pin probe measurements show that the electrical conductivity of AMV is improved by decreasing the particle size. The nanoparticle AMV shows higher initial discharge capacity and energy density than the as-prepared AMV when cycled at 0.5C. On the other hand, the nanoparticle AMV exhibits higher rate capability than the as-prepared AMV.

Recent progress of surface coating on cathode materials for high-performance lithium-ion batteries

Lithium-ion batteries (LIB) have received substantial attention in the last 10 years,as they offer great promise as power sources that can lead to the electric vehicle (EV) revolution in the next 5 years.Since the cathode serves as a key component in LIB,its properties significantly affect the performance of the whole system.Recently,the cathode surface modification based on coating technique has been widely employed to enhance the electrochemical performances by improving the material conductivity,stabilising the physical structure of materials,as well as preventing the reactions between the electrode and electrolyte.In this work,we reviewed the present of a number of promising cathode materials for Li-ion batteries.After that,we summarized the very recent research progress focusing on the surface coating strategies,mainly including the coating materials,the coating technologies,as well as the corresponding working mechanisms for cathodes.At last,the challenges faced and future guidelines for optimizing cathode materials are discussed.In this study,we propose that the structure of cathode is a crucial factor during the selection of coating materials and technologies.

Synthesis and characterization of triclinic structural LiVPO_4F as possible 4.2 V cathode materials for lithium ion batteries

A potential 4.2 V cathode material LiVPO4F for lithium batteries was prepared by two-step reaction method based on a carbon-thermal reduction （CTR） process. Firstly, V2O5, NH4H2PO4 and acetylene black are reacted under an Ar atmosphere to yield VPO4. The transition-metal reduction is facilitated by the CTR based on C→CO transition. These CTR conditions favor stabilization of the vanadium as V^3＋ as well as leaving residual carbon, which is useful in the subsequent electrode processing. Secondly, VPO4 reacts with ElF to yield LiVPO4F product. The property of the LiVPO4F was investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurement. XRD studies show that LiVPO4F synthesized has triclinic structure（space group p I ）, isostructural with the naturally occurring mineral tavorite, EiFePO4-OH. SEM image exhibits that the particle size is about 2μm together with homogenous distribution. Electrochemical test shows that the initial discharge capacity of LiVPO4F powder is 119 mA·h/g at the rate of 0.2C with an average discharge voltage of 4.2V （vs Ei/Li^＋）, and the capacity retains 89 mA·h/g after 30 cycles.

Microwave synthesis of Li_2FeSiO_4 cathode materials for lithium-ion batteries

A novel synthetic method of microwave processing to prepare Li2FeSiO4 cathode materials is adopted. The Li2FeSiO4 cathode material is prepared by mechanical ball-milling and subsequent microwave processing. Olivin-type Li2FeSiO4 sample with uniform and fine particle sizes is successfully and fast synthesized by microwave heating at 700 ℃ in 12 rain. And the obtained Li2FeSiO4 materials show better electrochemical performance and microstructure than those of Li2FeSiO4 sample by the conventional solidstate reaction. ？2009 Yan Bing Cao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Synthesis and electrochemical properties of Li[Ni_xCo_yMn_(1-x-y)]O_2 (x, y = 2/8, 3/8) cathode materials for lithium ion batteries

The tmiform layered Li（Ni2/8Co3/8Mn3/8）O2, Li（Ni3/8Co2/8Mn3/8）O2, and Li（Ni3/8Co3/8Mn2/8）O2 cathode materials for lithium ion batteries were prepared using the hydroxide co-precipitation method. The effects of calcination temperature and transition metal contents on the structure and electrochemical properties of the Li-Ni-Co-Mn-O were systemically studied. The results of XRD and electrochemical performance measurement show that the ideal preparation conditions were to prepare the Li（Ni3/8Co3/8Mn2/8）O2 cathode material calcined at 900℃ for 10 h. The well-ordered Li（Ni3/8Co3/8Mn2/8）O2 synthesized under the optimal conditions has the I003/I104 ratio of 1.25 and the R value of 0.48 and delivers the initial discharge capacity of 172.9 mA·h·g^-1, the discharge capacity of 166.2 mA·h·g^-1 after 20 cycles at 0.2C rate, and the impedance of 558 Ω after the first cycle. The decrease of Ni content results in the decrease of discharge capacity and the bad cycling performance of the Li-Ni-Co-Mn-O cathode materials, but the decreases of Mn content and Co content to a certain extent can improve the electrochemical properties of the Li-Ni-Co-Mn-O cathode materials.

Influence of Doping Rare Earth on Performance of Lithium Manganese Oxide Spinels as Cathode Materials for Lithium-Ion Batteries

Some rare earth doping spinel LiMn_(2-x)RE_xO_4 (RE=La, Ce, Nd) cathode materials for lithium ion batteries were synthesized by the solid-state reaction method. The structure characteristics of these produced samples were investigated by XRD, SEM, and particle size distribution analysis. According to the microstructure and charge-discharge testing, the effect of doping rare earth on stabilizing the spinel structure was analyzed. Through a series of doping experiments, it is shown that when the doping content x within the range of 0.01～0.02 the cycle performance of the materials is greatly improved. The discharge capacity of the sample LiMn_(1.98)La_(0.02)O_4, LiMn_(1.98)Ce_(0.02)O_4 and LiMn_(1.98)Nd_(0.02)O_4 remain 119.1, 114.2 and 117.5 mAh·g^(-1) after 50 cycles.

A closed-loop process for recycling LiNi_xCo_yMn_((1-x-y))O_2 from mixed cathode materials of lithium-ion batteries

With the rapid development of consumer electronics and electric vehicles(EV), a large number of spent lithium-ion batteries(LIBs) have been generated worldwide. Thus, effective recycling technologies to recapture a significant amount of valuable metals contained in spent LIBs are highly desirable to prevent the environmental pollution and resource depletion. In this work, a novel recycling technology to regenerate a LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 cathode material from spent LIBs with different cathode chemistries has been developed. By dismantling, crushing,leaching and impurity removing, the LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2(selected as an example of LiNi_xCo_yMn_(1-x-y)O_2) powder can be directly prepared from the purified leaching solution via co-precipitation followed by solid-state synthesis. For comparison purposes, a fresh-synthesized sample with the same composition has also been prepared using the commercial raw materials via the same method. X-ray diffraction(XRD), scanning electron microscopy(SEM) and electrochemical measurements have been carried out to characterize these samples. The electrochemical test result suggests that the re-synthesized sample delivers cycle performance and low rate capability which are comparable to those of the freshsynthesized sample. This novel recycling technique can be of great value to the regeneration of a pure and marketable LiNi_xCo_yMn_(1-x-y)O_2 cathode material with low secondary pollution.

Graphene oxide assisted facile hydrothermal synthesis of LiMn_(0.6)Fe_(0.4)PO_4 nanoparticles as cathode material for lithium ion battery

Assisted by graphene oxide（GO）,nano-sized LiMn0.6Fe0.4PO4 with excellent electrochemical performance was prepared by a facile hydrothermal method as cathode material for lithium ion battery.SEM and TEM images indicate that the particle size of LiMn0.6Fe0.4PO4（S2）was about 80 nm in diameter.The discharge capacity of LiMn0.6Fe0.4PO4 nanoparticles was 140.3 mAh-g^1 in the first cycle.It showed that graphene oxide was able to restrict the growth of LiMn0.6Fe0.4PO4 and it in situ reduction of GO could improve the electrical conductivity of LiMn0.6Fe0.4PO4 material.

Organic 3D interconnected graphene aerogel as cathode materials for high-performance aqueous zinc ion battery

Aqueous rechargeable zinc ion batteries are very attractive in large-scale storage applications,because they have high safety,low cost and good durability.Nonetheless,their advancements are hindered by a dearth of positive host materials(cathode)due to sluggish diffusion of Zn2+in the solid inorganic frameworks.Here,we report a novel organic electrode material of poly 3,4,9,10-perylentetracarboxylic dianhydride(PPTCDA)/graphene aerogel(GA).The 3D interconnected porous architecture synthesized through a simple solvothermal reaction,where the PPTCDA is homogenously embedded in the GA nanosheets.The self-assembly of PPTCDA/GA coin-type cell will not only significantly improve the durability and extend lifetime of the devices,but also reduce the electronic waste and economic cost.The self-assembled structure does not require the auxiliary electrode and conductive agent to prepare the electrode material,which is a simple method for preparing the coin-type cell and a foundation for the next large-scale production.The PPTCDA/GA delivers a high capacity of≥200 m Ah g^–1 with the voltage of 0.0~1.5 V.After 300 cycles,the capacity retention rate still close to 100%.The discussion on the mechanism of Zn2+intercalation/deintercalation in the PPTCDA/GA electrode is explored by Fourier transform infrared spectrometer(FT-IR),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)characterizations.The morphology and structure of PPTCDA/GA are examined by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).

Synthesis and electrochemical properties of Al-doped LiVPO_4F cathode materials for lithium-ion batteries

Al-doped LiVPO4F cathode materials LiAlxV1-xPO4F were prepared by two-step reactions based on a car-bothermal reduction （CTR） process. The properties of the Al-doped LiVPO4F were investigated by X-ray diffraction （XRD）,scanning electron microscopy （SEM）,and electrochemical measurements. XRD studies show that the Al-doped LiVPO4F has the same triclinic structure （space group p-↑1 ） as the undoped LiVPO4F. The SEM images exhibit that the particle size of Al-doped LiVPO4F is smaller than that of the undoped LiVPO4F and that the smallest particle size is only about 1 μm. The Al-doped LiVPO4F was evaluated as a cathode material for secondary lithium batteries,and exhibited an improved reversibility and cycleability,which may be attributed to the addition of Al^3＋ ion by stabilizing the triclinic structure.

A novel synthetic route for LiFePO_4/C cathode materials by addition of starch for lithium-ion batteries

LiFePO4/Carbon composite cathode material was prepared using starch as carbon source by spray-pelleting and subsequent pyrolysis in N2. The samples were characterized by XRD, SEM, Raman, and their electrochemical performance was investigated in terms of cycling behavior. There has a special micro-morphology via the process, which is favorable to electrochemical properties. The discharge capacity of the LiFePO4.C composite was 170 mAh g-1, equal to the theoretical specific capacity at 0.1 C rate. At 4 C current density, the specific capacity was about 80 mAh g-1, which can satisfy for transportation applications if having a more flat discharge flat.