Killing two birds with one stone: Constructing tri-elements doped and hollow-structured carbon sphere by a single template for advanced potassium-ion hybrid capacitors

Integrating the merits of long lifespan and excellent energy as well as power densities, potassium-ion hybrid capacitors (PIHCs) exhibit great prospects for future energy storage devices. To boost comprehensive performance of PIHCs, heteroatom-doping and morphology-tuning as two comprehensive strategies have been devoted to designing uniquely structural carbon-based materials with favorable advantages. An ideal strategy for simultaneous atomic doping and structural regulation is expected to be developed. Herein, we propose a novel Killing Two Birds with One Stone strategy to prepare a tri-elements doped hollow carbon sphere (TED-HCS) as PIHCs anodes, that is, a single template of spherical CoP particles is rationally adopted, which not only provides both a P source for heteroatom-doping but also acts as a selfsacrificial template for hollow-structure engineering. The multifunctional TED-HCS presents a high capacity of 473.0 mAh g(-1) and excellent rate performance of 212.5 mAh g(-1) at 5.0 A g(-1). Remarkably, the as-assembled PIHCs show outstanding energy/power density (40.4 Wh kg(-1)/10500 W kg(-1)) and remain high-capacity retention of 89.15% even cycling 12,000 times. The Killing Two Birds with One Stone strategy offers new insight into the search for the preparation of carbon-based materials with multi-elements doping and specific morphology structure. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

Potassium-ion hybrid capacitors (PIHCs) show great potential for future energy storage devices, with unique structural carbon-based materials designed through heteroatom-doping and morphology-tuning strategies to enhance their performance. A novel "Killing Two Birds with One Stone" strategy is proposed to prepare a tri-elements doped hollow carbon sphere (TED-HCS) for PIHCs, offering high capacity and excellent rate performance. The multi-functional TED-HCS demonstrates outstanding energy/power density and high-capacity retention even after 12,000 cycles, providing new insights into the preparation of carbon-based materials with multi-elements doping and specific morphology structures.