Toward Ultrahigh‐Rate Energy Storage of 3000 mV s−1 in Hollow Carbon: From Methodology to Surface‐to‐Bulk Synergy Insights

Abstract

AbstractDespite great efforts on economical and functionalized carbon materials, their scalable applications are still restricted by the unsatisfying energy storage capability under high‐rate conditions. Herein, theoretical and methodological insights for surface‐to‐bulk engineering of multi‐heteroatom‐doped hollow porous carbon (HDPC), with subtly designed Zn(OH)F nanoarrays as the template are presented. This fine‐tuned HDPC delivers an ultrahigh‐rate energy storage capability even at a scan rate of 3000 mV s−1 (fully charged within 0.34 s). It preserves a superior capacitance of 234 F g−1 at a super‐large current density of 100 A g−1 and showcases an ultralong cycling life without capacitance decay after 50 000 cycles. Through dynamic and theoretical analysis, the key role of in situ surface‐modified heteroatoms and defects in decreasing the K+‐adsorption/diffusion energy barrier is clarified, which cooperates with the porous conductive highways toward enhanced surface‐to‐bulk activity and kinetics. In situ Raman aids in visualizing the reversibly dynamic adsorption/releasing of the electrolyte ions on the tailored carbon structure during the charge/discharge process. The potential of the design concept is further evidenced by the enhanced performances in water‐in‐salt electrolytes. This surface‐to‐bulk nanotechnology opens the path for developing high‐performance energy materials to better meet the practical requirements in the future.