Composite Solid Electrolytes Based on Nickel-Doped Lithium Aluminum Silicate Ceramics Enable Lithium Metal Batteries with Enhanced Interfacial Stability and High-Rate Capability

Abstract

Solid-state electrolytes (SSEs) containing silicon or aluminum element can still not meet application requirements for relatively low ionic conductivity. Herein, we developed a series of nickel-doped lithium aluminum silicate ceramics, Li(1+0.05X)Al(1-0.05X)Ni0.05XSiO4 (X=0~3) (Ni-doped-LASO), with the strategy of aliovalent element doping. And then, a composite solid electrolyte (CSE, thickness = 30 μm), PMPV-LANSO-LiFSI-552, was fabricated with the obtained Li1.1Al0.9Ni0.1SiO4 (X=1), LANSO) ceramics as the SSE for good properties, a PMMA (polymethyl methacrylate)/PVDF (polyvinylidene fluoride) (6:4, w/w) blend (PMPV) as the polymer matrix, and LiFSI (lithium bis(fluorosulfonyl)imide) as additive electrolyte salt. The electrolyte exhibits an ionic conductivity of 0.84 mS cm⁻¹, a commendable Li⁺ transference number of 0.527 and a uniform Li+ ion deposition/exfoliation on the Li metal anode, realizing Li|CSE|Li cells stable cycle for 400 hours at 0.5 mA cm⁻² with a constant voltage of 24 mV. The Li‖LiFePO₄ (LFP) full cells with the CSE delivered a discharge capacity of 85.0 mAh g⁻¹ after 400 cycles at a rate of 10 C (1700 mAh g-1), 81.7% capacity retention with more than 99% Coulombic efficiency. Meanwhile, the Li‖LiNi0.8Co0.1Mn0.1O2 (NCM811) cells using the CSEs maintained 80% initial capacity after 180 cycles at 1 C (200 mAh g-1), demonstrating Compatibility with a high-voltage cathode. This developed CSE containing silicon or aluminum shows application prospect for solid-state lithium metal batteries with high electrochemical performance and low cost.