Enabling Rapid and Stable Sodium Storage via a P2-Type Layered Cathode with High-Voltage Zero-Phase Transition Behavior.

Currently, a major target in the development of Na-ion batteries is the concurrent attainment of high-rate capacity and long cycling stability. Herein, an advanced Na-ion battery with high-rate capability and long cycle stability based on Li/Ti co-doped P2-type Na 0.67 Mn 0.67 Ni 0.33 O 2 , a host material with high-voltage zero-phase transition behavior and fast Na + migration/conductivity during dynamic de-embedding process, is constructed. Experimental results and theoretical calculations reveal that the two-element doping strategy promotes a mutually reinforcing effect, which greatly facilitates the transfer capability of Na + . The cation Ti 4+ doping is a dominant high voltage, significantly elevating the operation voltage to 4.4 V. Meanwhile, doping Li + shows the function in charge transfer, improving the rate performance and prolonging cycling lifespan. Consequently, the designed P2-Na 0.75 Mn 0.54 Ni 0.27 Li 0.14 Ti 0.05 O 2 cathode material exhibits discharge capacities of 129, 104, and 85 mAh g - 1 under high voltage of 4.4 V at 1, 10, and 20 C, respectively. More importantly, the full-cell delivers a high initial capacity of 198 mAh g -1 at 0.1 C (17.3 mA g -1 ) and a capacity retention of 73% at 5 C (865 mA g -1 ) after 1000 cycles, which is seldom witnessed in previous reports, emphasizing their potential applications in advanced energy storage.