PNNL

Abstract

All-solid-state lithium batteries (ASSLB) utilizing solid polymer electrolytes (SPEs) present an attractive prospect for enhanced safety and simplified processing. However, their conventional operation requires elevated temperatures. Here, we dissect Li-ion transport processes within a SPE-based ASSLB and propose a straightforward hot-press activation method to enable cell operation at room temperature (r.t., 30 °C). This activation approach fundamentally promotes grain amorphization and significantly reduces grain boundary resistance within the SPE, leading to a fourfold increase in r.t. ionic conductivity. Furthermore, this activation significantly diminishes the electrode-electrolyte interfacial resistances for both the cathode and anode, thereby enhancing the kinetics and overall cell performance at r.t. Through the implementation of an optimized activation procedure, all solid-state LiFeO4 (LFP)|SPE|Li cells demonstrate remarkable performance improvements, delivering both high specific capacity and stable cycling at r.t.