A Perspective on the Origin of High-Entropy Solid Electrolytes

As the key material for the all-solid-state batteries (ASSBs), solid electrolytes (SEs) have attracted increasing attention. Recently, a novel design strategy-high-entropy (HE) approach is frequently reported to improve the ionic conductivity and electrochemical performance of SEs. However, the fundamental understandings on the HE working mechanism and applicability evaluation of HE concept are deficient, which would impede the sustainable development of a desirable strategy to enable high-performance SEs. In this contribution, the essence of HE-related approaches and their positive effects on SEs are evaluated. The reported HE strategy stems from complex compositional regulations. The derived structural stability and enhanced property are originally from the modulated system disorder and subtle local-structure evolutions, respectively. While HE ardently describes the increased entropy/disorder during the modification of prevailing SEs, rigorous experimental formulations, and direct correlations between the HE structures and desired properties are necessary to be established. This perspective would be a timely and critical overview for the HE approaches in the context of SEs, aiming to stimulate further discussion and exploration in this emerging research direction.