A bean catching double pigeons: Sonication assisted modification of Nb2C MXenes composites by O-doping porous biomass-carbons for supercapacitors and zinc-ion batteries

MXenes materials are novel promising candidates for the next generation energy storage devices. In this work, we designed a facile avenue using biomass derived carbons (PCarbons) and Nb 2 C MXenes as raw materials via sonication treatment to obtain Nb 2 C-PCarbons composites (Nb 2 C-PCarbons CPs). As a result, the prepared Nb 2 C-PCarbons CPs achieved a relative high specific capacitance up to 465.6 F·g −1 in the three-electrode system with 6 M KOH electrolyte. The fabricated symmetric supercapacitors (SSCs) displayed the ultra-high energy density (126.9 Wh·kg −1 ) in ion liquid electrolyte and the long cycling life after 10,000 cycles. Meanwhile, the obtained Nb 2 C-PCarbons CPs were also applied as cathode materials in the aqueous zinc ion batteries (AZIBs), achieving the maximum discharge specific capacity of ca. 239.7 mAh·g −1 with good cycling stability. Thus, our work provides an efficient method to modify the MXenes as bi-functional materials for the potential high-value utilization in SSCs and AZIBs.