Functional modules for enhanced amorphous composite halide solid electrolytes for low-temperature all-solid-state lithium batteries

Abstract Solid-state electrolytes (SSEs) are the essential component of all-solid-state batteries (ASSBs). Designing better SSEs holds the key to the success of the ASSBs. Here, this study effectively realises the design of SSEs through functional modules. Various functional designs have been achieved by incorporating different functional models. Here, we initially introduce LaCl 3 , which possesses a UCl 3 structure, as a functional module to demonstrate the feasibility of our approach. The Li 2 O-1.8TaCl 5 -0.2LaCl 3 (LTLOC) SSE enable the ASSB with LiNi 0.88 Co 0.09 Mn 0.03 O 2 (NCM88) to exhibit stable cycling and stable operation at low temperature (−30 °C). Additionally, various types of functional modules, including chloride, oxide, and fluoride, have been successfully introduced, further supporting the universality of amorphous functional module design. Furthermore, the incorporation of low-cost and low-density AlF 3 highlights the benefits of this design approach, as it allows for a high proportion of fluoride to be introduced without compromising ionic conductivity. Li 2 O-1.8TaCl 5 -5AlF 3 (LTOC-5AlF 3 ) exhibits stability in humid conditions, resistance to high voltage, and compatibility with lithium metal simultaneously. The key strength of this design approach is its ability to maintain advantages and make up for the shortcomings.