Promoting nitrogen-doped porous phosphorus spheres for high-rate lithium storage.

A nitrogen-doped porous phosphorus sphere features fast and robust ion-transport-pathways during lithiation/de-lithiation, delivering high-rate-capacity of 735 mAh g−1 at 20 A g−1 in half-cells and capacity-retention exceeding 90% after 200 cycles at 2 mA cm−2 in full-cells. [Display omitted] Phosphorus anode has shown great potential for the high-rate and high-energy–density lithium-ion batteries. Nevertheless, it still suffers from possible electrode cracking, ion-transport restrictions, and active-particle decomposition resulting from repeated alloying/de-alloying. To address the aforementioned issues, a nitrogen-doped flower-like porous phosphorus (f-P) sphere has been developed. The abundant micro-mesopores facilitate ion diffusion and enhance the internal bonding strength of the electrode. Concurrently, the doped nitrogen promotes the generation of a favorable solid electrolyte interphase constructed by fast-ion-conductors. As a result, the f-P exhibits a high-rate capacity of 735mAh g−1 at 20 A g−1 and maintains high Coulombic efficiencies over 900 cycles at 10 A g−1. Furthermore, coin full-cells comprising the f-P anode and lithium cobalt oxide cathode demonstrate stable operation at a high current density of 6 mA cm−2. The combination of a porous structure and doping strategy represents a viable approach for strengthening the durability of electrodes and optimizing the ion transport kinetics of advanced alloy anode materials. [ABSTRACT FROM AUTHOR]