High performance P-based argyrodite sulfide electrolytes enabled by Sb-based argyrodite doping for all-solid-state lithium metal batteries

Abstract

Sulfide-based solid electrolytes (SSEs) hold great prospects for realizing high-energy all-solid-state lithium metal batteries (ASSLMBs). However, the moisture sensitivity and Li-incompatibility of SSEs severely preclude their application. To address these issues, a Sb-based Li-argyrodite is selected as a novel dopant. The first-principles density functional theory calculations show that the simultaneous incorporation of Sn, Sb and I into a P-based electrolyte effectively reduces its Li-ion diffusion energy barriers, thus resulting in an outstanding ionic conductivity of 5.2 × 10⁻³ S cm⁻¹ at ambient temperature. Notably, the novel Li_6.02Sn_0.02Sb_0.03P_0.95S₅Cl_0.95I_0.05 presents remarkable interfacial stability against metallic Li. The Li symmetric cell can plate and strip for over 6000 h at 0.1 mA cm⁻² together with a high critical current density of 1.4 mA cm⁻². The Li₂O-coated LiNi_0.8Co_0.1Mn_0.1O₂/SSEs/Li ASSLMBs present a high initial discharge capacity of 181.0 mA h g⁻¹ at 0.1C and impressive rate capability. Furthermore, the assembled batteries using air-exposed electrolytes also exhibit unexpected cycling performance and rate capability owing to the conspicuously enhanced moisture resistance after doping with soft acids. Thus, the present study not only provides a suitable candidate for potential applications in high-performance ASSLMBs, but also gives new insights into the composition design and synthetic strategy of novel multi-element-doped materials.