Surface Defects Reinforced Polymer‐Ceramic Interfacial Anchoring for High‐Rate Flexible Solid‐State Batteries
Yanda Fu, Kai Yang, Shida Xue, Weihan Li, Shiming Chen, Yongli Song, Zhibo Song, Wenguang Zhao, Yunlong Zhao, Feng Pan, Luyi Yang, Xueliang Sun
Abstract
Abstract High Li + conductivity, good interfacial compatibility and high mechanical strength are desirable for practical utilization of all‐solid‐state electrolytes. In this study, by introducing Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) with surface defects into poly(ethylene oxide) (PEO), a composite solid electrolyte (OV‐LLZTO/PEO) is prepared. The surface defects serve as anchoring points for oxygen atoms of PEO chains, forming a firmly bonded polymer‐ceramic interface. This bonding effect effectively prevents the agglomeration of LLZTO particles and crystallization of PEO domains, forming a homogeneous electrolyte membrane exhibiting high mechanical strength, reduced interfacial resistance with electrodes as well as improved Li + conductivity. Owing to these favorable properties, 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, solid‐state full‐cells employing OV‐LLZTO/PEO deliver state‐of‐the‐art rate capability (8 C), power density and capacity retention. As a final proof of concept study, flexible pouch cells are assembled and tested, exhibiting high cycle stability under 5 C and excellent safety feature under abusive working conditions. Through manipulating the interfacial interactions between polymer and inorganic electrolytes, this study points out a new direction to optimizing the performance of all‐solid‐state batteries.