Enhancing d-p orbital coupling by Hf doping to construct a stable LiMn2O4 cathode for lithium-ion batteries

Spinel lithium manganate (LiMn2O4), a commonly used cathode material for lithium-ion batteries, undergoes unfavorable processes such as irreversible phase transition and Mn2+ dissolution during long-term cycling due to the deleterious Jahn-Teller distortion, leading to rapid capacity degradation. Herein, we introduce Hf into LiMn2O4 to induce 5d-2p orbital coupling and construct a stable Mn–O framework and thus suppressing the Jahn–Teller distortion, ultimately reducing Mn dissolution and the irreversible phase transitions. As a result, the tailored Hf-doped LiMn2O4 cathode delivers an extraordinarily high capacity of 119.9 mAh g-1 at 1 C, superior cyclability with 70.1% capacity retention after 1000 cycles at room temperature, and greatly enhanced rate capability. Furthermore, Hf-doped LiMn2O4 also shows good high-temperature tolerance, with 83.4% capacity retention after 400 cycles at 55 °C. This work presents an instructive contribution for constructing stable metal-oxygen framework via the introduction of orbital coupling, thus providing a promising strategy for constructing high-energy-density and high-stability cathode materials for lithium-ion batteries.