In-situ coupling construction of interface bridge to enhance electrochemical stability of all solid-state lithium metal batteries

Polymer-based composite electrolytes composed of three-dimensional Li_(6.4)La_(3)Zr_(2)Al_(0.2)O_(12)(3D-LLZAO)have attracted increasing attention due to their continuous ion conduction and satisfactory mechanical properties.However,the organic/inorganic interface is incompatible,resulting in slow lithium-ion transport at the interface.Therefore,the compatibility of organic/inorganic interface is an urgent problem to be solved.Inspired by the concept of“gecko eaves”,polymer-based composite solid electrolytes with dense interface structures were designed.The bridging of organic/inorganic interfaces was established by introducing silane coupling agent(3-chloropropyl)trimethoxysilane(CTMS)into the PEO-3D-LLZAO(PL)electrolyte.The in-situ coupling reaction improves the interface affinity,strengthens the organic/inorganic interaction,reduces the interface resistance,and thus achieves an efficient interface ion transport network.The prepared PEO-3D-LLZAO-CTMS(PLC)electrolyte exhibits enhanced ionic conductivity of 6.04×10^(-4)S cm^(-1)and high ion migration number(0.61)at 60℃and broadens the electrochemical window(5.1 V).At the same time,the PLC electrolyte has good thermal stability and high mechanical properties.Moreover,the Li Fe PO_(4)|PLC|Li battery has excellent rate performance and cycling stability with a capacity decay rate of 2.2%after 100 cycles at 60℃and 0.1 C.These advantages of PLC membranes indicate that this design approach is indeed practical,and the in-situ coupling method provides a new approach to address interface compatibility issues.

Scalable synthesized high-performance TiO_(2)-Si-C hybrid anode for lithium batteries

At present,developing a simple strategy to effectively solve the shackles of volume expansion,poor conductivity and interface compatibility faced by Si-C anode in lithium batteries(LIBs)is the key to its commercialization.Here,low-cost nano-Si powders were prepared from Si-waste of solar-cells by sanding treatment,which can effectively reduce the commercialization cost for Si-C anode.Furthermore,micro-nano structured Gr@Si/C/TiO_(2) anode materials with graphite(Gr)as the inner core,TiO_(2)-doped and carbon-coated Si as the outer coating-layer,were synthesized at kilogram-scale per milling batch.Comprehensive characterization results indicate that TiO_(2)-doped carbon layer can improve the interface compatibility with the electrolyte,further promote the reduction of electrode polarization,and finally enhance the battery performance for the Gr@Si/C/TiO_(2) anodes.Accordingly,Gr@Si/C/TiO_(2) composites can output excellent LIB performance,especially with high initial coulombic efficiency(ICE)of 82.51%and large average reversible capacity of~810 mA h g^(-1) at 0.8 A g^(-1) after 1000 cycles.Moreover,Gr@Si/C/TiO_(2)‖NCM811 pouch full cells deliver impressive performance especially with high energy density of~489.3 W h kg^(-1) based on the total weight of active materials,suggesting its promising application in the high performance LIBs.

Theoretical and experimental design in the study of sulfide-based solid-state battery and interfaces

In recent years,due to the increasing demand for portable electronic devices,rechargeable solid-state battery technology has developed rapidly.Lithium-ion batteries are the systems of choice,offering high energy density,flexible and lightweight design,and longer lifespan than comparable battery technologies.Therefore,a better understanding of the relationship between electrochemical mechanism and structural properties from theory and experiment will enable us to accelerate the development of high-performance and security batteries.This review discusses the interplay between theoretical calculation and experiment in the study of lithium ion battery materials.We introduce the application of theoretical calculation method in solid-state batteries through the combination of theory and experiment.We present the concept and assembly technology of solid-state batteries are reviewed.The basic parameters of solid-state electrolytes,especially sulfide-based solid-state electrolytes and their interface mechanisms with high-voltage cathode materials,are analyzed by theoretical methods.We present an overview on the scientific challenges,fundamental mechanisms,and design strategies for solid-state batteries,especially focusing on the issues of stability on solid-state electrolytes and the associated interfaces with both cathode and electrolyte.Owing to the theoretical models,we can not only reveal the unprecedented mechanism from the atomic scale,but also analyze the interface problems in the battery thoroughly,thus effectively designing more promising electrolyte and interface coating materials.It blazed a new trial for engineering an interphase with improved interfacial compatibility for a long-term cyclability.

Ameliorating the interfacial issues of all-solid-state lithium metal batteries by constructing polymer/inorganic composite electrolyte

Lithium metal is one of the most promising anodes for next-generation batteries due to its high capacity and low reduction potential.However,the notorious Li dendrites can cause the short life span and safety issues,hindering the extensive application of lithium batteries.Herein,Li_(7)La_(3)Zr_(2)O_(12)(LLZO)ceramics are integrated into polyethylene oxide(PEO)to construct a facile polymer/inorganic composite solid-state electrolyte(CSSE)to inhibit the growth of Li dendrites and widen the electrochemical stability window.Given the feasibility of our strategy,the designed PEO-LLZO-LiTFSI composite solid-state electrolyte(PLLCSSE)exhibits an outstanding cycling property of 134.2 mAh g^(-1) after 500 cycles and the Coulombic efficiency of 99.1%after 1000 cycles at 1 C in LiFePO_(4)-Li cell.When cooperated with LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cathode,the PLL-CSSE renders a capacity retention of 82.4%after 200 cycles at 0.2 C.More importantly,the uniform dispersion of LLZO in PEO matrix is tentative tested via Raman and FT-IR spectra and should be responsible for the improved electrochemical performance.The same conclusion can be drawn from the interface investigation after cycling.This work presents an intriguing solid-state electrolyte with high electrochemical performance,which will boost the development of all-solid-state lithium batteries with high energy density.

Block copolymer electrolyte with adjustable functional units for solid polymer lithium metal battery

Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes are still limited by the low ionic conductivity,poor interfacial contact with electrodes,narrow electrochemical window and weak mechanical strength.Here,a series of novel block copolymer electrolytes with three-dimensional networks are designed by cross-linked copolymerization of the polyethylene glycol soft segments and hexamethylene diisocyanate trimer hard segments.Their ionic migration performances and interface compatibilities with Li metal anode have been optimized delicately by tailoring the ratio of these functional units.The optimized block copolymer electrolyte has shown an amorphous crystalline structure,a high ionic conductivity of ~5.7×10^(-4)S cm^(-1),high lithium ion transference number(~0.49),wide electrochemical window up to ~4.65 V(vs.Li+/Li) and favorable mechanical strength at 55℃.Furthermore,the enhanced interface compatibility can well support the normal operations of lithium metal batteries using both LiFePO4 and LiNi0.8Co0.15Al0.05O2 cathodes.This study not only paves a new way to develop solid polymer electrolyte with optimizing functional units,but also provides a polymer electrolyte design strategy for the application demand of lithium metal battery.

Regulation of solvation structure and the cooperation environment of potassium bonds for wider-temperature adaptive potassium storage

Antimony selenide(Sb_(2)Se_(3))is one of the perspective candidates for potassium-ion batteries due to its advanced virtues stem including featured high capacity,fertile reserves and the relative narrow band gap.Despite the unique advantages,it is still plagued by the unstable interface compatibility and poor wider-temperature adaptability.The optimization of microstructure and the construction of inorganic-organic hybrids with a low desolvation barrier and rapid kinetics behaviors are efficient to address these issues.The Sb_(2)Se_(3)nanorods enclosed by the S-doped carbon layer(SC),further crosslinked by the poly(N-isopropylacrylamide)(PM)film(PM@Sb_(2)Se_(3)@SC),were artificially fabricated,and it displays the enrichment ion aggregated model as well as contacted ion pair state,the well-tailored cooperation environment of potassium bonds,assuring a homogeneous potassium deposition and an excellent widertemperature adaptability.The complicated experimental studies and theoretical calculations authenticate the synergistic effects of geometric conformation and compositional design for the tremendously enhanced potassium storage.Moreover,the full device over PM@Sb_(2)Se_(3)@SC anode and the potassium Prussian blue cathode manifests impressively durable cycling life and wider-temperature adaptability,verifying the glorious contribution from the finely manipulation in solvation structure and potassium bonds to enhancing the potassium storage behaviors.

Progress and perspectives of in situ polymerization method for lithium-based batteries

The application of lithium-based batteries is challenged by the safety issues of leakage and flammability of liquid electrolytes.Polymer electrolytes(PEs)can address issues to promote the practical use of lithium metal batteries.However,the traditional preparation of PEs such as the solution-casting method requires a complicated preparation process,especially resulting in side solvents evaporation issues.The large thickness of traditional PEs reduces the energy density of the battery and increases the transport bottlenecks of lithium-ion.Meanwhile,it is difficult to fill the voids of electrodes to achieve good contact between electrolyte and electrode.In situ polymerization appears as a facile method to prepare PEs possessing excellent interfacial compatibility with electrodes.Thus,thin and uniform electrolytes can be obtained.The interfacial impedance can be reduced,and the lithium-ion transport throughput at the interface can be increased.The typical in situ polymerization process is to implant a precursor solution containing monomers into the cell and then in situ solidify the precursor under specific initiating conditions,and has been widely applied for the preparation of PEs and battery assembly.In this review,we focus on the preparation and application of in situ polymerization method in gel polymer electrolytes,solid polymer electrolytes,and composite polymer electrolytes,in which different kinds of monomers and reactions for in situ polymerization are discussed.In addition,the various compositions and structures of inorganic fillers,and their effects on the electrochemical properties are summarized.Finally,challenges and perspectives for the practical application of in situ polymerization methods in solid-state lithium-based batteries are reviewed.

Design and Properties of Fluoroelastomer Composites via Incorporation of MWCNTs with Varied Modification

Multi-walled carbon nanotubes(MWCNTs)modified with silane coupling agent A-1120(MWCNTs-A1120)were prepared.Compared with the raw MWCNTs,acidified MWCNTs(MWCNTs-COOH),and MWCNTs grafted with EDA(MWCNTs-NH2),MWCNTs-A1120 have the best dispersion in fluoroelastomer at the same doping ratio.Therefore,fluoroelastomer/MWCNTs-A1120 composite has the best mechanical properties with tensile strength of 13.92 MPa and elongation at break of 111.78%.Then,the effects of doping amount of MWCNTs-A1120 on the electrical properties of the composites were investigated.The dielectric constant of the composite increases with the increase of MWCNTs-A1120,and the dielectric loss does not change much at the low doping amount such as 0.5 wt%.When the doping amount of MWCNTs-A1120 is 5 wt%,the dielectric constant and the dielectric loss value are greatly increased,and the volume resistivity is greatly decreased,which proves that the conductive network is formed in the composite,so the filling amount of 5 wt%is the percolation threshold.The tensile deformation of the sample also affects the electrical properties of the composites.As the tensile deformation increases,the dielectric constant and dielectric loss of the composite decrease.For the composite with 5 wt%MWCNTs-A1120,excessive tensile deformation will destroy the conductive network structure of the composite,so the composite will change from conductive material to dielectric material.Therefore,such composite is a good candidate for flexible conductive material or flexible dielectric material used in harsh environments such as high temperatures and various aggressive solvents.

Synthesis of two A-B-C type conjugated amphiphilic triblock fullerene derivatives and their application in organic solar cells

Two A-B-C type conjugated amphiphilic triblock fullerene derivatives C60-2 HMTPB and C60-2 EHTPB were obtained in multi steps synthesis with three different blocks,and the amphiphilic diblock molecular C60-4 TPB was also preferred as a reference.When as modifying layer on zinc oxide(ZnO),the three fullerene derivatives can all reduce the work function of ZnO via modulation of the interfacial dipoles and lead a better electrical coupling.As introducing treatment of toluene,the obvious self-assembly of fullerene derivatives were observed,which were supported by X-ray diffraction and contact angle of water measurement.Base on PTB7-Th:PC71 BM system,the inverted organic solar cells devices with structure of ITO/ZnO/fullerene derivatives/PTB7-Th:PC71BM/Mo03/Al got power conversion efficiencies of 8.62%,8.83%and 9.00%for C60-4 TPB,C60-2 HMTPB and C60-2 EHTPB,respectively,compared 8.13%of devices with bare ZnO.The result of conjugated amphiphilic triblock fullerene derivatives provides a straightforward approaching by simultaneously modulating the morphology and interfacial work function of ZnO,which can also lead high performance in optoelectronic devices.