Surface Defects Reinforced Polymer-Ceramic Interfacial Anchoring for High-Rate Flexible Solid-State Batteries

摘要

High Li~+ conductivity, good interfacial compatibility and high mechanicalstrength are desirable for practical utilization of all-solid-state electrolytes. Inthis study, by introducing Li_(6.4)La_3Zr_(1.4)Ta_(0.6)O_(12) (LLZTO) with surface defectsinto poly(ethylene oxide) (PEO), a composite solid electrolyte (OV-LLZTO/PEO) is prepared. The surface defects serve as anchoring points for oxygenatoms of PEO chains, forming a firmly bonded polymer-ceramic interface.This bonding effect effectively prevents the agglomeration of LLZTO particlesand crystallization of PEO domains, forming a homogeneous electrolytemembrane exhibiting high mechanical strength, reduced interfacial resistancewith electrodes as well as improved Li~+ conductivity. Owing to these favorableproperties, OV-LLZTO/PEO can be operated under a high current density(0.7 mA cm~(?2)) in a Li–Li symmetric cell without short circuit. Above all, solidstatefull-cells employing OV-LLZTO/PEO deliver state-of-the-art rate capability(8 C), power density and capacity retention. As a final proof of conceptstudy, flexible pouch cells are assembled and tested, exhibiting high cyclestability under 5 C and excellent safety feature under abusive working conditions.Through manipulating the interfacial interactions between polymer andinorganic electrolytes, this study points out a new direction to optimizing theperformance of all-solid-state batteries.