Optimizing Both Bulk and Surface Structure of Li‐Rich Layered Cathodes for Long‐Life and Safe Li‐Ion Batteries

Abstract

AbstractAlthough oxygen redox in Li‐rich layered cathodes can boost the available capacity over 250 mAh g−1, it also brings a rapid capacity fade upon long‐term cycling and serious safety issue during thermal abuse. To circumvent these problems, an integrated strategy via interlayer regulation at surface and the delocalization of Li2MnO3‐like domain on bulk is proposed. The controllable interlayer by atomic layer deposition can maximize the coating effects on elimination of the lattice mismatch to inhibit the structural degradation during cycling. And the delocalized Li2MnO3‐like domain through compositional control can fully prohibit lattice oxygen release from the bulk to improve the thermal stability of electrode. The optimized cathode material exhibits a capacity retention of 94.0% after 200 cycles. A 1.25 Ah multilayer pouch cell with the cathode and graphite anode delivers an outstanding cycling performance that retains 80.4% of its capacity at 0.5 C after 710 cycles. More importantly, the distinguished safety features derived from the method are verified after successfully passing practical‐level thermal safety and nail penetration test.