Preparation And Performance Of Of Li_6.75La₃Zr_1.75Ta_0.25O₁₂ And Na₃SbS₄ Composite Electrolytes

Solid-state batteries with high energy density can effectively avoid the potential safety hazard of commercial liquid battery.Solid electrolyte is the most important component in solid-state batteries.The research of new solid electrolytes with excellent performance is a direction for future all-solid-state battery applications.In addition,the solid-solid contact between the electrolyte and the electrodes in all-solid-state batteries is poor,the interface problem is nasty.Therefore,through interface engineering to reduce interface impedance effectively is also an important way to improve the performance of all-solid-state batteries in the future.In this paper,the organic-inorganic composite solid electrolyte membranes are obtained by combining different inorganic particles and polymers,which effectively improve the interface problems and has excellent electrochemical performance.Li_6.75La₃Zr_1.75Ta_0.25O₁₂(LLZTO)particles(6.25 wt.%)was added in PCL matrix to prepare polymer composite electrolyte.The introduced of LLZTO can reduce the crystallinity of the polymer and improve the ionic conductivity.The obtained“Ceramic in Polymer”(CIP)composite electrolyte has high ion conductivity of 0.169 m S/cm,wide electrochemical window of 4.5 V and ion transference number of 0.44,and also exhibits good interface stability with metal lithium.The assembled all-solid-state battery also shows good cycle performance.However,the mechanical properties of these electrolytes need to be further improved.“Polymer in ceramic”(PIC)composite electrolyte was obtained by compounding inorganic particles LLZTO(52.5 wt.%)and polycaprolactone PCL in order to further enhance the mechanical strength of polymer composite electrolyte.Furthermore,trace of dimethyl carbonate(DMC)is introduced through the method of vapor absorption to effectively alleviate the interface problem between the electrolyte and the electrode.The ionic conductivity of PIC-DMC composite electrolyte reached to 3.1 m S/cm at room temperature,and also has high ion transference number of 0.67 and wide electrochemical window of 4.7 V.The mechanical strength of the electrolyte is improved by filling a large number of inorganic particles.The introduction of trace DMC increases the ion transport path,and effectively improves the interface problem and electrochemical performance of the electrolyte.The PVDF-NSS-0.2IL composite electrolyte is prepared by introducing Na₃Sb S₄inorganic particles and trace of ionic liquid BMPTFSI into the PVDF porous membrane.The uniform pores on the surface of the PVDF membrane effectively regulate the homogeneous deposition of Na⁺to avoid the formation of dendrites.The introduction of trace ionic liquids,which not only connects Na₃Sb S₄ particles to form an ion transport network,but also can effectively improve the interface problem between electrolyte and electrode.All solid-state batteries assembled using PVDF-NSS-0.2IL composite membranes exhibit excellent cycle stability.