Design of High‐Entropy Tape Electrolytes for Compression‐Free Solid‐State Batteries

Abstract

Advanced solid electrolytes with strong adhesion to other components are the key for the successes of solid‐state batteries. Unfortunately, traditional solid electrolytes have to work under high compression to maintain the contact inside owing to their poor adhesion. Here, a concept of high entropy tape electrolyte (HETE) is proposed to simultaneously achieve tape‐like adhesion, liquid‐like ion‐conduction and separator‐like mechanical properties. This HETE is designed with adhesive skin‐layer on both sides and robust skeleton‐layer in the middle. The significant properties of the three layers are enabled by high‐entropy microstructures which are realized by harnessing polymer‐ion interactions. As a result, the HETE shows high ionic conductivity (3.50 ± 0.53×10−4 S cm−1 at R.T), good mechanical properties (toughness 11.28 ± 1.12 MJ m−3, strength 8.18 ± 0.28 MPa), and importantly, tape‐like adhesion (interfacial toughness 231.6 ± 9.6 J m−2). Moreover, a compression‐free solid‐state tape battery is finally demonstrated by adhesion‐based assembling, which shows good interfacial and electrochemical stability even under harsh mechanical conditions, such as twisting and bending. The concept of HETE and compression‐free solid‐state tape batteries may bring promising solutions and inspiration to conquer the interface challenges in solid‐state batteries and their manufacturing.This article is protected by copyright. All rights reserved

More is better: high-entropy electrolyte design in rechargeable batteries

“…He et al prepared a high-entropy tape electrolyte (HETE) with a sandwiched configuration. 81 In this system, the high-entropy skin layer consisted of fully amorphous PEO–Li + complexes, which facilitated fast Li + transport and provided strong adhesion. The middle layer, which incorporated PVDF/Li + /PEO with high mixing entropy, was achieved through Li + -enhanced compatibilization between PVDF and PEO, improving the mechanical properties of the electrolyte.…”

Working Principles of High-Entropy Electrolytes in Rechargeable Batteries

“…For some allsolid-state polymer electrolytes, the interior is dominated by structural entropy and elastic entropy to enhance mechanical properties. 39 This indicates that it is not feasible to determine the high-entropy state by applying the S config . Furthermore, the entropy of many solid-state HEEs does not satisfy the definition of entropy in high-entropy alloys, because most of them are codoped materials that do not have sufficient entropy, or even have lower entropy.…”

“…For instance, the S config of SSEs with given compositions and hypothetical model structure or crystal structures containing only one anion and cation site can be calculated using eq . ,, However, there are still several problems with regard to the distinction of entropy for solid-state HEEs. For some all-solid-state polymer electrolytes, the interior is dominated by structural entropy and elastic entropy to enhance mechanical properties . This indicates that it is not feasible to determine the high-entropy state by applying the S config .…”

“…Yang et al proposed a double-sided adhesive-type solid-state HEE based on high-entropy structural design by integrating high-entropy microstructures of polymer chains (Figure a) . The solid-state HEE exhibits a high ionic conductivity (3.50 ± 0.53 × 10 –4 S cm –1 ), ideal mechanical properties (strength of 8.18 ± 0.28 MPa, strain at break of 186.0 ± 12.8%), and strong surface adhesion (interfacial toughness of 231.6 ± 9.6 J m –2 ).…”

“…Solid-state batteries in the traditional "sandwich" structure cannot achieve a tight and stable interfacial contact due to the lack of liquid electrolyte wetting. 38 Wang et al 39 designed a solid-state HEE through polymer-ion synthesis, where a tape-like adhesion is achieved at the interface to enhance the interfacial contacting capability. (6) Gaps between scientific and industrial research.…”