Chemomechanically Stable Small Single‐crystal Mo‐doped LiNi0.6Co0.2Mn0.2O2 Cathodes for Practical 4.5 V‐class Pouch‐type Li‐ion Batteries

High voltage can cost‐effectively boost energy density of Ni‐rich cathodes based Li‐ion batteries (LIBs), but compromises their mechanical, electrochemical and thermal‐driven stability. Herein, a collaborative strategy (i.e., small single‐crystal design and hetero‐atom doping) is devised to construct a chemomechanically reliable small single‐crystal Mo‐doped LiNi0.6Co0.2Mn0.2O2 (SS‐MN6) operating stably under high voltage (≥4.5 V vs. Li/Li+). The substantially reduced particle size combined with Mo6+ doping absorbs accumulated localized stress to eradicate cracks formation, subdues the surface side reactions and lattice oxygen missing meanwhile, and improves thermal tolerance at highly delithiated state. Consequently, the SS‐MN6 based pouch cells are endowed with striking deep cycling stability and wide‐temperature‐tolerance capability. The contribution here provides a promising way to construct advanced cathodes with superb chemomechanical stability for next‐generation LIBs. Small single‐crystal Mo‐doped LiNi0.6Co0.2Mn0.2O2 with high chemomechanical reliability is constructed, and exhibits high‐rate capacities, long‐duration life, and low thermal activity under highly delithiated states for wide‐temperature‐tolerance Li‐ion batteries as competitive cathodes.