Single-atom Zn for boosting supercapacitor performance

Single-atom metal-incorporated carbon nanomaterials(CMs)have shown great potential towards broad catalytic applications.In this work,we show that N-doped porous CMs embedded with redox-able Zn atoms exhibit superior capacitive performance.High Zn(~2.72 at.%)/N(~12.51 at.%)doping were realized by incorporating Zn2+and benzamide into the condensation and carbonization of formamide and subsequent annealing at 900℃.The Zn and N species are mutually benefited during the formation of ZnN4 motif.The as-obtained Zn1NC material affords a very large capacitance of 621 F·g^(−1)(at 0.1 A·g^(−1)),superior rate capability(~65%retention at 100 A·g^(−1)),and excellent cycling stability(0.00044%per cycle at 10 A·g^(−1)).These merits are attributed to the high Zn/N loading,atomic Zn-boosted pseudocapacitive behavior,large specific surface area(~1,085 m^(2)·g^(−1)),and rich pore hierarchy,thus ensuring both large pseudo-capacitance(e.g.,~37.9%at 10 mV·s^(−1))and double-layer capacitance.Besides of establishing a new type of high Zn/N-loading carbon materials,our work uncovers the capacitive roles of atomically dispersed metals in CMs.