Prussian blue analogue derived Al-doped CoN core-shell decorated by N-doped MXene quantum dots for solid-state asymmetrical supercapacitors

초록

Highly efficient electrode nanostructures are urgently needed for realizing ultrahigh energy density in portable and miniaturized electronics. Metal nitride–based electrodes hold promise for supercapacitor fabrication owing to their high electrical conductivity, redox activity, and mechanical strength, but have not been commercialized because of their low electrochemical stability. Herein, an ecofriendly and scalable “one-for-two” calcination strategy is used to convert carbon nitride sheets and an aluminum cobalt Prussian blue analog (AlCoPBA) into aluminum-doped cobalt nitride (AlCoN) nanocrystals encapsulated by (1) nitrogen-doped carbon decorated with MXene quantum dots (AlCoN@NC-MXQDs) and (2) nitrogen-doped carbon nanotubes (AlCoN@N-CNTs) with three-dimensional core–shell and hierarchical structures. These two composites have been evaluated as supercapacitor cathode materials. AlCoN@NC-MXQDs exhibited a specific capacity 2.4 times that of AlCoN@N-CNTs (314.4 mAh/g vs. 130.1 mAh/g, respectively) and an excellent cycle stability (95 % capacity retention after 10000 cycles). The solid-state asymmetric device obtained by pairing an AlCoN@NC-MXQD cathode with a nitrogen-doped graphene decorated with zinc-doped iron nitride (ZnFeN@NG) anode can deliver an ultrahigh energy density (96.5 Wh/kg), power density (507 W/kg), and cycling stability (capacity retention of 90 % after 10000 cycles), thus performing on par with previously reported asymmetric supercapacitors. Thus, our study paves the way for designing new core–shell structures to be exploited as electroactive materials in flexible electronics. © 2025 Elsevier B.V.

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