Monolayer MoS_(2)Fabricated by In Situ Construction of Interlayer Electrostatic Repulsion Enables Ultrafast Ion Transport in Lithium-Ion Batteries

High theoretical capacity and unique layered structures make MoS_(2)a promising lithium-ion battery anode material.However,the anisotropic ion transport in layered structures and the poor intrinsic conductivity of MoS_(2)lead to unacceptable ion transport capability.Here,we propose in-situ construction of interlayer electrostatic repulsion caused by Co^(2+)substituting Mo^(4+)between MoS_(2)layers,which can break the limitation of interlayer van der Waals forces to fabricate monolayer MoS_(2),thus establishing isotropic ion transport paths.Simultaneously,the doped Co atoms change the electronic structure of monolayer MoS_(2),thus improving its intrinsic conductivity.Importantly,the doped Co atoms can be converted into Co nanoparticles to create a space charge region to accelerate ion transport.Hence,the Co-doped monolayer MoS_(2)shows ultrafast lithium ion transport capability in half/full cells.This work presents a novel route for the preparation of monolayer MoS_(2)and demonstrates its potential for application in fast-charging lithium-ion batteries.

One-Pot Synthesis of Co-Based Coordination Polymer Nanowire for Li-Ion Batteries with Great Capacity and Stable Cycling Stability

Nanowire coordination polymer cobalt–terephthalonitrile(Co-BDCN) was successfully synthesized using a simple solvothermal method and applied as anode material for lithium-ion batteries(LIBs). A reversible capacity of 1132 mAh g^(-1) was retained after 100 cycles at a rate of 100 mAg^(-1), which should be one of the best LIBs performances among metal organic frameworks and coordination polymers-based anode materials at such a rate. On the basis of the comprehensive structural and morphology characterizations including fourier transform infrared spectroscopy,~1 H NMR,^(13)C NMR, and scanning electron microscopy, we demonstrated that the great electrochemical performance of the as-synthesized Co-BDCN coordination polymer can be attributed to the synergistic effect of metal centers and organic ligands, as well as the stability of the nanowire morphology during cycling.

Synthesis and Electrochemical Studies on Spinel Phase LiMn_2O_4 Cathode Materials Prepared by Different Processes

Three kinds of processes, high temperature solid state reaction, precipitation and solgel technique were used to synthsize spinel phase LiMn2O4. XRD, DTATG results show that phasepure spinel LiMn2O4 could be synthesized under the lowest calcined temperature by the solgel technique compared to the precipitation method and solid state reaction. BET, SEM and electrochemical measurements results demonstrate that the features of the powders affect directly the electrochemical capacities; large specific area and small homogeneous grain size are of advantage for the lithium ion insertion and extraction in the charge and discharge process.

Optimization of LiMn_2O_4 electrode properties in a gradient-and surrogate-based framework

In this study, the effects of discharge rate and LiMn2O4 cathode properties （thickness, porosity, particle size, and solid-state diffusivity and conductivity） on the gravimetric energy and power density of a lithium-ion battery cell are analyzed simultaneously using a cell-level model. Surrogate-based analysis tools are applied to simulation data to construct educed-order models, which are in turn used to perform global sensitivity analysis to compare the relative importance of cathode properties. Based on these results, the cell is then optimized for several distinct physical scenarios using gradient-based methods. The comple-mentary nature of the gradient-and surrogate-based tools is demonstrated by establishing proper bounds and constraints with the surrogate model, and then obtaining accurate optimized solutions with the gradient-based optimizer. These optimal solutions enable the quantification of the tradeoffs between energy and power density, and the effect of optimizing the electrode thickness and porosity. In conjunction with known guidelines, the numerical optimization frame-work developed herein can be applied directly to cell and pack design.

High-capacity organic electrode material calix[4] quinone/CMK-3 nanocomposite for lithium batteries

Organic lithium-ion batteries（OLIBs） represent a new generation of power storage approach for their environmental benignity and high theoretical specific capacities.However, it has the disadvantage with regard to the dissolution of active materials in organic electrolyte. In this study, we encapsulated high capacity material calix[4]quinone（C4Q） in the nanochannels of ordered mesoporous carbon（OMC）CMK-3 with various mass ratios ranging from 1：3 to 3：1, and then systematically investigated their morphology and electrochemical properties. The nanocomposites characterizations confirmed that C4Q is almost entirely capsulated in the nanosized pores of the CMK-3 while the mass ratio is less than2：1. As cathodes in lithium-ion batteries, the C4Q/CMK-3（1：2） nanocomposite exhibits optimal initial discharge capacity of 427 mA h g^（-1） with 58.7% cycling retention after 100 cycles. Meanwhile, the rate performance is also optimized with a capacity of 170.4 mA h g^（-1） at 1 C. This method paves a new way to apply organic cathodes for lithium-ion batteries.

Depositing natural stibnite on 3D TiO_(2) nanotube array networks as high-performance thin-film anode for lithium-ion batteries

Three-dimensional(3D) thin-film electrodes are promising solution to the volume change of active materials in lithium-ion batteries.As a conductive current collector,the 3D TiO_(2) nanotube array networks(TNAs) have a one-dimensional stable electronic conductive path and increase the adhesion between the current collector and raw material,thereby improving the cycle stability of active materials.In this study,a novel 3D-TNAs@Sb_(2)S_(3) anode was fabricated by directly depositing natural stibnite onto3D TNAs.The adhesion of Sb_(2)S_(3) particles to the substrate was enhanced due to the large surface area provided by 3D-TNAs.Moreover,the porous layered structure composed of Sb_(2)S_(3) nanoparticles relieved the stress generated during lithiation and adapted to the volume change of Sb_(2)S_(3) during cycling.Therefore,the resulting composite anode exhibits high cycle and rate performance,reaching0.36 mAh·cm^(-2) after 80 cycles at the galvanostatic rate of1 mA·cm^(-2),with high coulombic efficiency of 98%.

Progress on the Fault Diagnosis Approach for Lithium-ion Battery Systems:Advances,Challenges,and Prospects

Because of their advantages of high energy and power density,low self-discharge rate,and long lifespan,lithium-ion batteries(LIBs)have been widely used in many applications such as electric vehicles,energy storage systems,smart grids,etc.However,lithium-ion battery systems(LIBSs)frequently malfunction because of complex working conditions,harsh operating environment,battery inconsistency,and inherent defects in battery cells.Thus,safety of LIBSs has become a prominent problem and has attracted wide attention.Therefore,efficient and accurate fault diagnosis for LIBs is very important.This paper provides a comprehensive review of the latest re-search progress in fault diagnosis for LIBs.First,the types of battery faults are comprehensively introduced and the characteristics of each fault are analyzed.Then,the fault diagnosis methods are systematically elaborated,including model-based,data processing-based,machine learn-ing-based and knowledge-based methods.The latest re-search is discussed and existing issues and challenges are presented,while future developments are also prospected.The aim is to promote further researches into efficient and advanced fault diagnosis methods for more reliable and safer LIBs.Index Terms—Battery management system,battery safety,fault diagnosis,lithium-ion battery system.

Facile synthesis and electrochemical properties of layered Li[Ni1/3Mn1/3Co1/3]O2 as cathode materials for lithium-ion batteries

A layered oxide Li[Ni1/3Mn1/3Co1/3]O2 was synthesized by an oxalate co- precipitation method. The morphology, structural and composition of the as-papered samples synthesized at different calcination temperatures were investigated. The results indicate that calcination temperature of the sample at 850℃ can improve the integrity of structural significantly. The effect of calcination temperature varying from 750℃ to 950℃ on the electrochemical performance of Li[Ni1/3Mn1/3Co1/3]O2, cathode material of lithiumion batteries, has been investigated. The results show that Li[Ni1/3Mn1/3Co1/3]O2 calcined at 850℃ possesses a higher capacity retention and better rate capability than other samples. The reversible capacity is up to 178.6 mA.h.g-1, and the discharge capacity still remains 176.3 mA-h.g-1 after 30 cycles. Moreover, our strategy provides a simple and highly versatile route in fabricating cathode materials for lithium-ion batteries.

Metal-organic framework-derived Ni2P/nitrogendoped carbon porous spheres for enhanced lithium storage

Transition metal phosphides(TMPs)/carbonaceous matrices have gradually attracted attention in the field of energy storage.In this study,we presented nickel phosphide(Ni2P)nanoparticles anchored to nitrogen-doped carbon porous spheres(Ni2P/NC)by using metal-organic framework-Ni as the template.The comprehensive encapsulation architecture provides closer contact among the Ni2P nanoparticles and greatly improves the structural integrity as well as the electronic conductivity,resulting in excellent lithium storage performance.The reversible specific capacity of 286.4 mA hg^-1 has been obtained even at a high current density of 3.0 Ag^-1 and 450.4 mA hg^-1 is obtained after 800 cycles at 0.5 Ag^-1.Furthermore,full batteries based on LiNi1/3Co1/3Mn1/3O2||Ni2P/NC exhibit both good rate capability and cycling life.This study provides a powerful and indepth insight on new advanced electrodes in high-performance energy storage devices.

Bimetallic zeolite imidazolate framework for enhanced lithium storage boosted by the redox participation of nitrogen atoms

In this work, a bimetallic zeolitic imidazolate framework （ZIF） CoZn-ZIF was synthesized via a facile sol-vothermal approach and applied in lithiumion batteries. The as-prepared CoZn-ZIF shows a high reversible capacity of 605.8 mA b g-i at a current density of 100 mA g^-1, far beyond the performance of the corresponding monometallic Co-ZIF- 67 and Zn-ZIF-8. Ex-situ synchrotron soft X-ray absorption spectroscopy, X-ray diffraction, and electron paramagnetic resonance techniques were employed to explore the Li^storage mechanism. The superior performance of CoZn-ZIF over Co-ZIF-67 and Zn-ZIF-8 could be mainly attributed to lithiation and delithiation of nitrogen atoms, accompanied by the breakage and recoordination of metal nitrogen bond. Morever, a few metal nitrogen bonds without recoordination will lead to the amorphization of CoZn-ZIF and the formation of few nitrogen radicals.

Effects of gradient concentration on the microstructure and electrochemical performance of LiNi0.6Co0.2Mn0.2O2 cathode materials

Nickel(Ni)-rich layered materials have attracted considerable interests as promising cathode materials for lithium ion batteries(LIBs)owing to their higher capacities and lower cost.Nevertheless,Mn-rich cathode materials usually suffer from poor cyclability caused by the unavoidable side-reactions between Ni^4+ions on the surface a nd electrolytes.The design of gradient concentration(GC)particles with Ni-rich inside and Mn-rich outside is proved to be an efficient way to address the issue.Herein,a series of LiNi0.6Co0.2Mn0.2O2(LNCM 622)materials with different GCs(the atomic ratio of Ni/Mn decreasing from the core to the outer layer)have been successfully synthesized via rationally designed co-precipitation process.Experimental results demonstrate that the GC of LNCM 622 materials plays an important role in their microstructure and electrochemical properties.The as-prepared GC3.5 cathode material with optimal GC can provide a shorter pathway for lithium-ion diffusion and stabilize the near-surface region,and finally achieve excellent electrochemical performances,delivering a discharge capacity over 176 mAh·g^-1 at 0.2 C rate and exhibiting capacity retention up to 94%after 100 cycles at 1 C.T h e rationally-designed co-precipitation process for fabricating the Ni-rich layered cathode materials with gradient composition lays a solid foundation for the preparation of high-performance cathode materials for LIBs.

Machine learning in energy storage materials

With its extremely strong capability of data analysis,machine learning has shown versatile potential in the revolution of the materials research paradigm.Here,taking dielectric capacitors and lithium‐ion batteries as two representa-tive examples,we review substantial advances of machine learning in the research and development of energy storage materials.First,a thorough discussion of the machine learning framework in materials science is presented.Then,we summarize the applications of machine learning from three aspects,including discovering and designing novel materials,enriching theoretical simulations,and assisting experimentation and characterization.Finally,a brief outlook is highlighted to spark more insights on the innovative implementation of machine learning in materials science.

Structure and electrochemical performance of Ba Li_(2-x)Na_xTi_6O_(14)(0≤x≤2) as anode materials for lithium-ion battery

A series of Ba Li_（2-x）NaxTi_6O_（14）（0≤x≤2） compounds as lithium storage materials were synthesized by a facile solidstate method. X-ray diffraction Rietveld refinement shows that the Bragg positions correspond to the Ba Li_2Ti_6O_（14）, indicating a successful preparation. The Na＋ions doped Ba Li_2-Ti_6O_（14） compounds have larger unit-cell volume than the pristine one because ionic radius of Na＋ion is 55% larger than that of Li＋ion. SEM shows that the Ba Li_2-xNaxTi_6O_（14）（x=0, 0.5 and1） powders show similar irregular shaped particles between500 and 1000 nm. However, Ba Li_2-xNaxTi_6O_（14）（x=1.5 and 2）powders show similar rod-like shape. CV reveals that the passivating film is mainly formed during the first insertion process, and the solid electrolyte interface film on the surface of Ba Li_2-xNaxTi_6O_（14）（0≤x≤2） is formed below 0.7 V in the first cycle. Compared with other samples, Ba Li_0.5Na1.5Ti_6O_（14） exhibits higher reversible capacity, better rate capability and superior cyclability. Ba Li_0.5Na1.5Ti_6O_（14） delivers the delithiation capacities of 162.1 mAhg^-（1）at 50 m A g^-（1）, 158.1 mAhg^-（1）at 100 m A g^-（1）, 156.7 mAhg^-（1）at 150 m A g^-（1）, 152.2 mAhg^-（1）at 200 m A g^-（1）, 147.3 mAhg^-（1）at 250 m A g^-（1）and 142 mAhg^-（1）at 300 m A g^-（1）, respectively. An interesting thing is that Ba Na2Ti_6O_（14） as anode also shows an acceptable electrochemical performance. All these improved electrochemical performances of Ba Li_0.5Na1.5Ti_6O_（14） are attributed to the lowest polarization and the highest lithium ion diffusion coefficient among all samples.Hence, Ba Li_0.5Na1.5Ti_6O_（14） with excellent cycling performance,simple synthesis route and wide discharge voltage range can be a possible anode candidate for lithium-ion batteries.