Dual-doped carbon hollow nanospheres achieve boosted pseudocapacitive energy storage for aqueous zinc ion hybrid capacitors

Rechargeable aqueous zinc ion hybrid capacitors (ZHCs) have attracted increasing attention for energy storage devices due to low cost, high safety and environmental friendliness. However, it suffers from low energy/power density and poor cycling stability due to the lack of suitable electrode materials, especially the promising cathode candidates with satisfactory capacity and excellent cycling stability. Herein, we developed dual-doped carbon hollow nanospheres (PN-CHoNS) through a dual-functional template induced strategy combined with the subsequent carbonization treatment, which can act as potential cathode materials. Impressively, when employed to assemble the ZHCs, the device can deliver an exceptional energy density of 116.0 Wh kg−1 at a power density of 141 W kg−1 and an extremely high power density of 21660 W kg−1 under a decent energy density of 36.1 Wh kg−1, as well as ultra-long cycling stability up to 12000 cycles. Moreover, the systematic characterization and density functional theory calculation decipher that dual-doping could promote the chemical absorption/desorption kinetics of Zn ions to boost the electrochemical charge storage of carbon. This work can not only provide a rational strategy to construct advanced carbon-based electrode materials, but also deepen the fundamental understanding of the charge storage mechanism of heteroatom-doped carbonaceous materials.