Enhancing room temperature performance of solid-state lithium cell via a facile solid electrolyte-cathode interface design

Abstract

Herein, we report the enhanced electrochemical performance of a solid-state cell realized through an engineered solid electrolyte-cathode interface via a simple casting technique. The ceramic-in-polymer solid electrolyte sample with 15 wt% NASICON-type Li1�2Sn0�9Zr0�9Al0�2(PO4)3 ceramic filler in a P(VDF-HFP) matrix (CPSE15) showed the highest room temperature conductivity of ?1.1 � 10?4 S cm?1 and lithium-ion transference number of ?0.60. The symmetric Li|CPSE15|Li cell showed a consistent voltage profile with an over-potential of ?45 mV for 750 h at a current density of 0.1 mA cm?2. CPSE15 slurry was directly cast onto the LiFePO4 (LFP) cathode layer using a doctor-blade coating method to obtain a cathode-electrolyte assembly. Subsequently, a full cell fabricated using this assembly and lithium metal delivered an initial discharge capacity of ?157 mAh g?1 at 0.2C. Further, the cell exhibited ?90 mAh g?1 discharge capacity at 1C and sustained 500 charge-discharge cycles at room temperature. The engineered interface in cathode-electrolyte assembly enabled this cell to outperform its conventionally fabricated counterpart with a stacked LFP cathode sheet and freestanding CPSE15 electrolyte membrane, which was attributed to a lower interfacial resistance (?51%) of the former. � 2024 Elsevier Ltd