ABSTRACT Achieving high energy, power densities, and long‐term cycling stability under harsh conditions remains a core challenge for sodium‐ion hybrid capacitors (SIHCs). Here we propose a multiscale charge‐polarization strategy by introducing a spiny hollow carbon sphere (SHCS) anode featuring a tip‐enhanced “lightning‐rod effect.” These densely distributed microscale tips induce local charge accumulation, forming fast ion/electron transport channels. Coupled with 12.6 at% N‐doping, the SHCS exhibits expanded interlayer spacing and enriched delocalized electron density, thereby accelerating Na + adsorption and migration across multiple scales. Finite element analysis and DFT simulations confirm the synergistic roles of spiny structure and heteroatom doping in enhancing ionic/electronic transport kinetics. As expected, the SHCS anode delivers an excellent specific capacity of 408 mAh g −1 at 0.1 A g −1 and maintains stable cycling even at 30.0 A g −1 . When assembled with a commercial activated carbon (AC), the AC||SHCS SIHCs exhibit a high specific capacity of 237.6 mAh g −1 at 25°C and a high energy density of 63.9 Wh kg −1 at 5281 W kg −1 as well as outstanding low‐temperature tolerance (93.3 mAh g −1 at −40°C). This work offers a scalable structural design principle for carbon anodes and demonstrates a promising path toward next‐generation high‐performance and all‐climate SIHCs.
Qi et al. (Fri,) studied this question.