Rechargeable Lithium Metal Batteries with an In‐Built Solid‐State Polymer Electrolyte and a High Voltage/Loading Ni‐Rich Layered Cathode

Abstract

Abstract Solid‐state batteries enabled by solid‐state polymer electrolytes (SPEs) are under active consideration for their promise as cost‐effective platforms that simultaneously support high‐energy and safe electrochemical energy storage. The limited oxidative stability and poor interfacial charge transport in conventional polymer electrolytes are well known, but difficult challenges must be addressed if high‐voltage intercalating cathodes are to be used in such batteries. Here, ether‐based electrolytes are in situ polymerized by a ring‐opening reaction in the presence of aluminum fluoride (AlF 3 ) to create SPEs inside LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM) || Li batteries that are able to overcome both challenges. AlF 3 plays a dual role as a Lewis acid catalyst and for the building of fluoridized cathode–electrolyte interphases, protecting both the electrolyte and aluminum current collector from degradation reactions. The solid‐state NCM || Li metal batteries exhibit enhanced specific capacity of 153 mAh g −1 under high areal capacity of 3.0 mAh cm −2 . This work offers an important pathway toward solid‐state polymer electrolytes for high‐voltage solid‐state batteries.