Microwave Engineering of Manganese‐Rich Layered‐Spinel Cathode Materials for Enhanced Lithium‐Ion Battery Performance

Layered oxides such as the Mn‐rich lithium nickel manganese cobalt oxides are promising next‐generation lithium‐ion battery cathode materials owing to the abundance and environmental benignity of Mn. However, the first‐cycle irreversibility loss and voltage decay remain key drawbacks that need to be addressed urgently. Herein, rational microwave irradiation is used to induce in situ generation of spinel phase in the bulk of a LiMn 0.662 Ni 0.173 Co 0.165 O 2 material. The layered‐spinel heterostructured cathode material delivers excellent cycling stability, with a continuous increase in discharge capacity until the 80th cycle at 0.1 C, thereafter showing a capacity decay of 12.9% when further cycled for 70 cycles, while also displaying suppressed voltage decay 4.11 mV cycle −1 throughout these 150 cycles. Electrochemical impedance spectroscopy studies also show improved lithium diffusion kinetics. To establish the underlying science behind the impact of microwave irradiation, several characterization techniques attribute the observed excellent performance to i) lattice expansion, ii) suppressed Li + /Ni 2+ cation mixing, iii) fine‐tuned morphology, iv) increased average manganese oxidation state, and v) increased lattice oxygen in the material. This work showcases the potential of microwave‐assisted synthesis methods in designing cathode materials with tuned physico‐chemical properties, and thus improved electrochemistry.