Facile Self-Templated Synthesis of P2-type Na0.7CoO2 Microsheets as Long-Term Cathode for High-Energy Sodium-ion Battery
Sodium-ion batteries are one of the most promising candidates for large-scale energy storage system due to the low cost of sodium source and similar working principle to lithium-ion batteries. However, the demerit of poor cycling stability of cathode severely restricts the advance of sodium-ion battery based practical applications. Herein, we report a facile self-template directed two-step strategy to fabricate with greatly enhanced high rate cycling stability when applied as cathode for SIBs. Specifically, it can deliver a high specific capacity of 137.7 mAh g-1 at a current density of 10 mA g-1 and exhibit impressive long-term cycling stability with a capacity retention of 94% after 1000 cycles at a high rate of 500 mA g-1, which is outstanding compared with previous results for layered metal oxide cathodes. More importantly, the sodium-ion full cell based on the P2-type Na0.7CoO2 microsheet cathode is further built to demonstrate the possibilities for practical applications, where inspiring results can be observed with promising cycling stability and high power/energy densities. This work demonstrates the great potential of layered metal oxide cathodes in practical applications, which could push forward the advance of grid-level energy storage system.