Lattice-Bulk Regulation Enables Internal Stress Mitigation toward Ultra-stable Nickel-rich Layered Cathodes

Nickel-rich layered cathode materials are predominantly used for lithium-ion batteries owing to their high specific capacities and minimal use of high-cost cobalt. However, their structural instability detrimentally affects the battery performance during cell cycling. The intrinsic drawbacks with regard to capacity retention and structure stability have largely been addressed by lattice-bulk regulation. Conventionally, doping strategy considers only the incorporation of additional elements into the bulk structure of the cathode in terms of fortifying the crystal structure. Herein, we report a lattice-bulk regulation strategy for single-crystalline LiNi 0.92 Co 0.04 Mn 0.04 O 2 (SNCM) cathodes by doping B/Zr to tackle instability and boost electrochemical performance. B ions are adequately incorporated in TM lattice to enhanced crystal structure and relief the internal strain, while Zr ions with low solubility tend to gather on the SNCM surface layer, which inhibits the mixing of Li/Ni cations during high cut-off voltage cycles. The synergistic effect of co-doping forms a stable cathode-electrolyte interface to inhibit side reactions at the interface, and improves the transmission of lithium ions. Benefiting from these favorable characteristics, we assembled a 1.8 Ah pouch cell capable of delivering high discharge specific capacity of 164.2 mAh g -1 after 1500 cycles with 82.3% of capacity retention. The B/Zr dual modification strategy was adopted to prevent the occurrence of side reactions and dissolution of transition metals. B ions were uniformly distributed in the lattice, enhancing the crystal structure and reducing internal strain. Zr ions tended to aggregate on the surface of the particles, which inhibited the mixing of Li/Ni cations and the occurrence of phase transitions.