Mitigating Crosstalk by Slurry Additive Toward 5 V Cobalt‐Free LiNi0.5Mn1.5O4 Cathode

Abstract LiNi 0.5 Mn 1.5 O 4 (LNMO), with its spinel symmetry, emerges as a promising cathode material for high‐voltage lithium‐ion batteries (LIBs). Nonetheless, the vulnerability of LNMO to interfacial degradation, particularly electrolyte breakdown during high‐voltage operation, compromises its long‐term cycling performance. To overcome this longstanding challenge, a slurry additive—polyester‐urethane‐acrylate (PEUA)—to form a multi‐functional ultra‐thin electrode coating, enhancing the lifespan and energy density of LIBs is introduced. Comprehensive characterizations and theoretical analyses reveal that the PEUA slurry additive effectively maintains electrode integrity, facilitates electrons and lithium ions transport, and inhibits hazardous side reactions, thus preventing the by‐products from triggering cathode‐electrolyte‐anode interface crosstalk. Consequently, the 5 V LNMO || Li cell with PEUA slurry additive maintains a high‐capacity retention of 97.8%, with improved cycling stability at high‐temperature and full‐cell configurations. This crosstalk‐mitigation strategy offers a promising avenue for extending the lifespan and electrochemical performance of high‐voltage cobalt‐free cathodes, advancing the practical use of high‐energy density LIB technology.