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.

Empowering the Future: Exploring the Construction and Characteristics of Lithium-Ion Batteries

Lithium element has attracted remarkable attraction for energy storage devices, over the past 30 years. Lithium is a light element and exhibits the low atomic number 3, just after hydrogen and helium in the periodic table. The lithium atom has a strong tendency to release one electron and constitute a positive charge, as Li . Initially, lithium metal was employed as a negative electrode, which released electrons. However, it was observed that its structure changed after the repetition of charge-discharge cycles. To remedy this, the cathode mainly consisted of layer metal oxide and olive, e.g., cobalt oxide, LiFePO4, etc., along with some contents of lithium, while the anode was assembled by graphite and silicon, etc. Moreover, the electrolyte was prepared using the lithium salt in a suitable solvent to attain a greater concentration of lithium ions. Owing to the lithium ions’ role, the battery’s name was mentioned as a lithium-ion battery. Herein, the presented work describes the working and operational mechanism of the lithium-ion battery. Further, the lithium-ion batteries’ general view and future prospects have also been elaborated.

Laminar Composite Solid Electrolyte with Poly(Ethylene Oxide)-Threaded Metal-Organic Framework Nanosheets for High-Performance All-Solid-State Lithium Battery

Developing laminar composite solid electrolyte with ultrathin thickness and continuous conduction channels in vertical direction holds great promise for all-solid-state lithium batteries.Herein,a thin,laminar solid electrolyte is synthesized by filtrating–NH 2 functionalized metal-organic framework nanosheets and then being threaded with poly(ethylene oxide)chains induced by the hydrogen-bonding interaction from–NH_(2) groups.It is demonstrated that the threaded poly(ethylene oxide)chains lock the adjacent metal-organic framework nanosheets,giving highly enhanced structural stability(Young’s modulus,1.3 GPa)to 7.5-μm-thick laminar composite solid electrolyte.Importantly,these poly(ethylene oxide)chains with stretching structure serve as continuous conduction pathways along the chains in pores.It makes the non-conduction laminar metal-organic framework electrolyte highly conductive:3.97×10^(−5) S cm^(−1) at 25℃,which is even over 25 times higher than that of pure poly(ethylene oxide)electrolyte.The assembled lithium cell,thus,acquires superior cycling stability,initial discharge capacity(148 mAh g^(−1) at 0.5 C and 60℃),and retention(94% after 150 cycles).Besides,the pore size of nanosheet is tailored(24.5–40.9˚A)to evaluate the mechanisms of chain conformation and ion transport in confined space.It shows that the confined pore only with proper size could facilitate the stretching of poly(ethylene oxide)chains,and meanwhile inhibit their disorder degree.Specifically,the pore size of 33.8˚A shows optimized confinement effect with trans-poly(ethylene oxide)and cis-poly(ethylene oxide)conformation,which offers great significance in ion conduction.Our design of poly(ethylene oxide)-threaded architecture provides a platform and paves a way to the rational design of next-generation high-performance porous electrolytes.

All-solid-state lithium batteries with inorganic solid electrolytes:Review of fundamental science

The scientific basis of all-solid-state lithium batteries with inorganic solid electrolytes is reviewed briefly, touching upon solid electrolytes, electrode materials, electrolyte/electrode interface phenomena, fabrication, and evaluation. The challenges and prospects are outlined as well.

Poly(carbonate)-based ionic plastic crystal fast ion-conductor for solid-state rechargeable lithium batteries

Liquid plasticizers with a relatively higher dielectric coefficient like ethylene carbonate(EC),propylene carbonate(PC),and ethyl methyl carbonate(EMC) are the most commonly used electrolyte materials in commercial rechargeable lithium batteries(LIBs) due to their outstanding dissociation ability to lithium salts.However,volatility and fluidity result in their inevitable demerits like leakage and potential safety problem of the final LIBs.Here we for the first time device a subtle method to prepare a novel thermal-stable and non-fluid poly(carbonate) solid-state electrolyte to merge EC with lithium carriers.To this aim,a series of carbonate substituted imidazole ionic plastic crystals(G-NTOC) with different polymerization degrees have been synthesized.The resulting G-NTOC shows an excellent solid-state temperature window(R.T.-115℃).More importantly,the maximum ionic conductivity and lithium transference number of the prepared G-NTOC reach 0.36 × 10^(-3) S cm^(-1) and 0.523 at 30℃,respectively.Galvanostatic cycling test results reveal that the developed G-NTOC solid-state electrolytes are favorable to restraining the growth of lithium dendrite due to the excellent compatibility between the electrode and the produced plastic crystal electrolyte.The fabricated LiIG-NTOCILiFeP04 all-solid-state cell initially delivers a maximum discharge capacity of 152.1 mAh g^(-1) at the discharge rate of 0.1 C.After chargingdischarging the cell for 60 times,Coulombic efficiency of the solid-state cell still exceeds 97%.Notably,the LiIG-NTOCILiFeP04 cell can stably light a commercial LED with a rated power of 0.06 W for more than1 h at 30℃,and the output power nearly maintains unchanged with the charging-discharging cycling test,implying a sizeable potential application in the next generation of solid-state LIBs.

CNTs@S composite as cathode for all-solid-state lithium-sulfur batteries with ultralong cycle life

The main challenges in development of traditional liquid lithium-sulfur batteries are the shuttle effect at the cathode caused by the polysulfide and the safety concern at the Li metal anode arose from the dendrite formation.All-solid-state lithium-sulfur batteries have been proposed to solve the shuttle effect and prevent short circuits.However,solid-solid contacts between the electrodes and the electrolyte increase the interface resistance and stress/strain,which could result in the limited electrochemical performances.In this work,the cathode of all-solid-state lithium-sulfur batteries is prepared by depositing sulfur on the surface of the carbon nanotubes(CNTs@S)and further mixing with Li10GeP2S12 electrolyte and acetylene black agents.At 60℃,CNTs@S electrode exhibits superior electrochemical performance,delivering the reversible discharge capacities of 1193.3,959.5,813.1,569.6 and 395.5 mAhg^-1 at the rate of 0.1,0.5,1,2 and 5 C,respectively.Moreover,the CNTs@S is able to demonstrate superior high-rate capability of 660.3 mAhg^-1 and cycling stability of 400 cycles at a high rate of 1.0 C.Such uniform distribution of the CNTs,S and Li10GeP2S12 electrolyte increase the electronic and ionic conductivity between the cathode and the electrolyte hence improves the rate performance and capacity retention.

Investigation of Li-ion transport in Li7P3S11 and solid-state lithium batteries

The high Li-ion conductivity of the Li7P3S11 sulfide-based solid electrolyte makes it a promising candidate for all-solid-state lithium batteries. The Li-ion transport over electrode-electrolyte and electrolyteelectrolyte interfaces, vital for the performance of solid-state batteries, is investigated by impedance spectroscopy and solid-state NMR experiments. An all-solid-state Li-ion battery is assembled with the Li7P3S11 electrolyte, nano-Li2S cathode and Li-In foil anode, showing a relatively large initial discharge capacity of 1139.5 m Ah/g at a current density of 0.064 m A/cm^ 2 retaining 850.0 m Ah/g after 30 cycles. Electrochemical impedance spectroscopy suggests that the decrease in capacity over cycling is due to the increased interfacial resistance between the electrode and the electrolyte. 1D exchange ^7Li NMR quantifies the interfacial Li-ion transport between the uncycled electrode and the electrolyte, resulting in a diffusion coefficient of 1.70(3) ×10^-14cm^2/s at 333 K and an energy barrier of 0.132 e V for the Li-ion transport between Li2S cathode and Li7P3S11 electrolyte. This indicates that the barrier for Li-ion transport over the electrode-electrolyte interface is small. However, the small diffusion coefficient for Li-ion diffusion between the Li2S and the Li7P3S11 suggests that these contact interfaces between electrode and electrolyte are relatively scarce, challenging the performance of these solid-state batteries.

Interfacial Issues of All Solid State Lithium Batteries

All solid state lithium battery is a promising next generation battery system with improved cycle life, en ergy density, especially safety. However, its development is greatly hampered by a large impedance between the solid state electrolyte/electrode interface. How to build an ideal electrolyte/electrode interface to improve the inter facial stability and reduce the interracial resistance is a huge challenge for improving battery performance. This pa per reviews interracial problems and introduces the formation mechanism of different interface layers between elec trodes and electrolytes. In addition, the strategies for improving interracial contact and reducing interracial resist ance are described in detail. Finally, the research directions for engineering interfaces in all solid state lithium bat teries are proposed.

Supercritical-hydrothermal accelerated solid state reaction route for synthesis of LiMn_2O_4 cathode material for high-power Li-ion batteries

Synthesis of the spinel structure lithium manganese oxide （LiMn2O4） by supercritical hydrothermal （SH） accelerated solid state reaction （SSR） route was studied. The impacts of the reaction pressure, reaction temperature and reaction time of SH route, and the calcination temperature of SSR route on the purity, particle morphology and electrochemical properties of the prepared LiMn2O4 materials were studied. The experimental results show that after 15 min reaction in SH route at 400 ℃ and 30 MPa, the reaction time of SSR could be significantly decreased, e.g. down to 3 h with the formation temperature of 800 ℃, compared with the conventional solid state reaction method. The prepared LiMn2O4 material exhibits good crystallinity, uniform size distribution and good electrochemical performance, and has an initial specific capacity of 120 mA.h/g at a rate of 0.1C （1C=148 mA/g） and a good rate capability at high rates, even up to 50C.

A Comparative Study of Fractional Order Models on State of Charge Estimation for Lithium Ion Batteries

State of charge(SOC)estimation for lithium ion batteries plays a critical role in battery management systems for electric vehicles.Battery fractional order models(FOMs)which come from frequency-domain modelling have provided a distinct insight into SOC estimation.In this article,we compare five state-of-the-art FOMs in terms of SOC estimation.To this end,firstly,characterisation tests on lithium ion batteries are conducted,and the experimental results are used to identify FOM parameters.Parameter identification results show that increasing the complexity of FOMs cannot always improve accuracy.The model R(RQ)W shows superior identification accuracy than the other four FOMs.Secondly,the SOC estimation based on a fractional order unscented Kalman filter is conducted to compare model accuracy and computational burden under different profiles,memory lengths,ambient temperatures,cells and voltage/current drifts.The evaluation results reveal that the SOC estimation accuracy does not necessarily positively correlate to the complexity of FOMs.Although more complex models can have better robustness against temperature variation,R(RQ),the simplest FOM,can overall provide satisfactory accuracy.Validation results on different cells demonstrate the generalisation ability of FOMs,and R(RQ)outperforms other models.Moreover,R(RQ)shows better robustness against truncation error and can maintain high accuracy even under the occurrence of current or voltage sensor drift.

Lithium-ion transport in inorganic solid state electrolyte

An overview of ion transport in lithium-ion inorganic solid state electrolytes is presented, aimed at exploring and de signing better electrolyte materials. Ionic conductivity is one of the most important indices of the performance of inorganic solid state electrolytes. The general definition of solid state electrolytes is presented in terms of their role in a working cell （to convey ions while isolate electrons）, and the history of solid electrolyte development is briefly summarized. Ways of using the available theoretical models and experimental methods to characterize lithium-ion transport in solid state elec- trolytes are systematically introduced. Then the various factors that affect ionic conductivity are itemized, including mainly structural disorder, composite materials and interface effects between a solid electrolyte and an electrode. Finally, strategies for future material systems, for synthesis and characterization methods, and for theory and calculation are proposed, aiming to help accelerate the design and development of new solid electrolytes.

Improving ionic conductivity of polymer-based solid electrolytes for lithium metal batteries

Because of its superior safety and excellent processability,solid polymer electrolytes(SPEs)have attracted widespread attention.In lithium based batteries,SPEs have great prospects in replacing leaky and flammable liquid electrolytes.However,the low ionic conductivity of SPEs cannot meet the requirements of high energy density systems,which is also an important obstacle to its practical application.In this respect,escalating charge carriers(i.e.Li^(+))and Li^(+)transport paths are two major aspects of improving the ionic conductivity of SPEs.This article reviews recent advances from the two perspectives,and the underlying mechanism of these proposed strategies is discussed,including increasing the Li^(+)number and optimizing the Li^(+)transport paths through increasing the types and shortening the distance of Li^(+)transport path.It is hoped that this article can enlighten profound thinking and open up new ways to improve the ionic conductivity of SPEs.

LiNbO3-coated LiNi0.8Co0.1Mn0.1O2 cathode with high discharge capacity and rate performance for all-solid-state lithium battery

In order to obtain high power density,energy density and safe energy storage lithium ion batteries(LIB)to meet growing demand for electronic products,oxide cathodes have been widely explored in all-solidstate lithium batteries(ASSLB)using sulfide solid electrolyte.However,the electrochemical performances are still not satisfactory,due to the high interfacial resistance caused by severe interfacial instability between sulfide solid electrolyte and oxide cathode,especially Ni-rich oxide cathodes,in charge-discharge process.Ni-rich LiNi0.8Co0.1Mn0.1O2(NCM811)material at present is one of the most key cathode candidates to achieve the high energy density up to 300 Wh kg^-1 in liquid LIB,but rarely investigated in ASSLB using sulfide electrolyte.To design the stable interface between NCM811 and sulfide electrolyte should be extremely necessary.In this work,in view of our previous work,LiNbO3 coating with about 1 wt% content is adopted to improve the interfacial stability and the electrochemical performances of NCM811 cathode in ASSLB using Li10GeP2S12 solid electrolyte.Consequently,LiNbO3-coated NCM811 cathode displays the higher discharge capacity and rate performance than the reported oxide electrodes in ASSLB using sulfide solid electrolyte to our knowledge.

Machine learning of materials design and state prediction for lithium ion batteries

With the widespread use of lithium ion batteries in portable electronics and electric vehicles,further improvements in the performance of lithium ion battery materials and accurate prediction of battery state are of increasing interest to battery researchers.Machine learning,one of the core technologies of artificial intelligence,is rapidly changing many fields with its ability to learn from historical data and solve complex tasks,and it has emerged as a new technique for solving current research problems in the field of lithium ion batteries.This review begins with the introduction of the conceptual framework of machine learning and the general process of its application,then reviews some of the progress made by machine learning in both improving battery materials design and accurate prediction of battery state,and finally points out the current application problems of machine learning and future research directions.It is believed that the use of machine learning will further promote the large-scale application and improvement of lithium-ion batteries.

Fuzzy Model for Estimation of the State-of-Charge of Lithium-Ion Batteries for Electric Vehicles

A fuzzy model was established to estimate the state of charge（SOC） of a lithium-ion battery for electric vehicles.The robust Gustafson-Kessel（GK） clustering algorithm based on clustering validity indices was applied to identify the structure and antecedent parameters of the model.The least squares algorithm was utilized to determine the consequent parameters.Validation results show that this model can provide accurate SOC estimation for the lithium-ion battery and satisfy the requirement for practical electric vehicle applications.

Self-assembly synthesis of solid polymer electrolyte with carbonate terminated poly (ethylene glycol) matrix and its application for solid state lithium battery

A facile one-pot synthesis of solid polymer electrolytes(SPEs), composed of carbonate terminated poly(ethylene glycol)(CH3O-PEG-IC), poly(ethylene glycol)-block-polystyrene(PEG-b-PS) block copolymer nanoparticles containing a conductive PEG corona, fumed SiO2 and Li TFSI salt via polymerization-induced self-assembly is proposed. This method to prepare SPEs has the advantages of one-pot convenient synthesis, avoiding use of organic solvent and conveniently adding inorganic additives. CH3O-PEG-IC combines advantages of PEG and polycarbonate, the in situ synthesized PEG-b-PS nanoparticles containing a rigid polystyrene(PS) core and a PEG corona guarantee continuous lithium ion transport in the synthesized SPEs, and the fumed SiO2 optimizes the interfacial properties and improves the electrochemical stability, all of which afford SPEs a well considerable room temperature ionic conductivity of 1.73 × 10^-4S/cm, high lithium transference number of 0.53, and wide electrochemical stability window of 5.5 V(vs. Li^+/Li). By employing these SPEs, the assembled solid state cells of Li FePO4 |SPEs|Li exhibit considerable cell performance.

Solid-State Electrolytes for Lithium-Sulfur Batteries

Secondary lithium-sulfur batteries have attracted extensive attention due to their high energy density,low cost and environment friendly.However,the"shuttle effect"of polysulfides dissolved in liquid electrolytes leads to a decrease of the cell Coulomb efficiency(CE).Therefore,researchers have used solid electrolytes instead of traditional liquid electrolytes and separators to suppress the"shuttle effect"of polysulfides and the growth of lithium dendrites.The progress in electrolytes for solid-state lithium-sulfur batteries including solid-state polymer,inorganic,and composite electrolytes to solve the issues is summarized.

Porous garnet as filler of solid polymer electrolytes to enhance the performance of solid-state lithium batteries

In order to enhance the ionic conductivity of solid polymer electrolytes(SPEs)and their structural rigidity against lithium dendrite during lithium-ion battery(LIB)cycling,we propose porous garnet Li6.4La3Zr2Al0.2O12(LLZO),as the filler to SPEs.The porous LLZO with interlinked grains was synthesized via a resol-assisted cationic coordinative co-assembly approach.The porous structure of LLZO with high specific surface area facilitates the interaction between polymer and filler and provides sufficient entrance for Li^(+)migration into the LLZO phase.Furthermore,the interconnection of LLZO grains forms continuous inorganic pathways for fast Li^(+)migration,which avoid the multiple diffusion for Li^(+)in interface.As a result,the SPEs with porous LLZO(SPE-PL)show a high ionic conductive of 0.73 mS·cm^(-1) at 30℃ and lithium-ion transference number of 0.40.The porous LLZO with uniformly dispersed pores also acts as an ion distributor to regulate ionic flux.The lithium-symmetrical batteries assembled with SPE-PL show a highly stable Li plating/stripping cycling for nearly 3000 h at 0.1 mA·cm^(-2).The corresponding Li/LiFePO_(4) batteries also exhibit excellent cyclic performance with capacity retention of 75%after nearly 500 cycles.This work brings new insights into the design of conductive fillers and the optimization of SPEs.

Reaction mechanisms for 0.5Li_2MnO_3 ·0.5LiMn_(0.5)Ni_(0.5)O_2 precursor prepared by low-heating solid state reaction

Lithium-excess manganese layered oxides, which are commonly described in chemical formula 0.5Li2MnO3·0.5LiMn0.5Ni0.5O2, were prepared by low-heating solid state reaction. The reaction mechanisms of synthesizing precursors, the decomposition mechanism, and intermediate materials in calcination were investigated by means of Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD）, field emission scanning electron microscopy （FESEM）, thermogravimetric analysis （TGA）, and differential scanning calorimetry （DSC）. The major diffraction patterns of 0.5Li2MnO3·0.5LiMn0.5Ni0.5O2 powder calcinated at 720℃ for 15 h are indexed to the hexagonal structure with a space group of R3m, and the clear splits of doublets at （006）/（102） and （108）/（110） indicate that the sample adopts a well-layered structure. FESEM images show that the size of the agglomerated particles of the sample ranges from 100 to 300 nm.

A Comparative Study on Open Circuit Voltage Models for Lithium-ion Batteries

The current research of state of charge(SoC) online estimation of lithium-ion battery(LiB) in electric vehicles(EVs)mainly focuses on adopting or improving of battery models and estimation filters. However, little attention has been paid to the accuracy of various open circuit voltage(OCV) models for correcting the SoC with aid of the ampere-hour counting method. This paper presents a comprehensive comparison study on eighteen OCV models which cover the majority of models used in literature. The low-current OCV tests are conducted on the typical commercial LiFePO/graphite(LFP) and LiNiMnCoO/graphite(NMC) cells to obtain the experimental OCV-SoC curves at different ambient temperature and aging stages. With selected OCV and SoC points from experimental OCV-SoC curves, the parameters of each OCV model are determined by curve fitting toolbox of MATLAB 2013. Then the fitting OCV-SoC curves based on diversified OCV models are also obtained. The indicator of root-mean-square error(RMSE) between the experimental data and fitted data is selected to evaluate the adaptabilities of these OCV models for their main features, advantages,and limitations. The sensitivities of OCV models to ambient temperatures, aging stages, numbers of data points,and SoC regions are studied for both NMC and LFP cells. Furthermore, the influences of these models on SoC estimation are discussed. Through a comprehensive comparison and analysis on OCV models, some recommendations in selecting OCV models for both NMC and LFP cells are given.