Designing Polymer-in-Salt Electrolyte and Fully Infiltrated 3D Electrode for Integrated Solid-State Lithium Batteries.

Abstract

Solid-state lithium batteries (SSLBs) are very promising due to their enhanced safety and high energy density, but greatly plagued by the relatively low ionic conductivity of solid-state electrolytes and large electrolyte-electrode interfacial resistance. Herein, we design a\xa0poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based polymer-in-salt solid electrolyte (PISSE) with high room-temperature ionic conductivity (1.24×10 -4 S cm -1 ) and construct a model integrated TiO 2 /Li SSLB with 3D fully infiltration of solid electrolyte. With forming aggregated ion clusters, unique ionic channels are generated in the PISSE, providing much faster Li + transport than common polymer electrolytes. Moreover, the integrated device simultaneously achieves maximized interfacial contact and electrochemical and mechanical stability, presenting high performance close to that with liquid electrolyte. A pouch cell made of 2 SSLB units in series shows high voltage plateau (3.7 V) and volumetric energy density comparable to many commercial thin-film batteries (microbatteries), which also exhibits robust flexibility and brilliant safety under abuse tests.