Achieving High Performance Aqueous Zn-Ion Batteries via Interfacial Coating of N, P Dual-Doped Biomass Porous Carbon on Zn Metal Anode

Aqueous zinc-ion batteries (AZIBs) have significant potential as a large-scale energy storage device due to their low cost and high safety. However, the formation of zinc dendrites during repeated plating and stripping and complicated side reactions has seriously hindered the development of AZIBs. Herein, a N, P dual-doped biomass carbon was constructed by a simple hydrothermal and pyrolysis strategy. In this case, N and P heteroatoms increased the defects of biomass carbon and made it easier to form a uniform and stable interface with the zinc metal. On the other hand, the interfacial interactions between Zn2+ and the biomass carbon surface were enhanced by the introduction of zincophilic groups, which lowered the energy barriers required for zinc nucleation, resulting in uniform zinc deposition. Therefore, symmetric batteries assembled with Zn anodes based on N and P dual-doped biomass carbon exhibited outstanding cycling stability (2000 h) and relatively small voltage hysteresis (45 mV) at a current density of 1 mA cm–2 and an area capacity of 0.15 mAh cm–2. Besides, with a VO2 cathode to compose a full battery, the capacity of the NPBC@Zn//VO2 battery was 132.2 mAh g–1 after 1500 cycles at 5 A g–1, with 76.8% capacity retention. It is much higher than the 27.7% of the Zn//VO2 battery. This work demonstrates a novel two-element-doped biomass carbon/Zn anode interface modification strategy to achieve dendrite-free Zn anodes in AZIBs.