Metal-organic frameworks derived porous carbon nanonecklaces with boosted specific capacitance and energy density towards high-performance electrochemical energy storage

By virtue of the inherent safety, decent power density and low manufacturing cost, zinc-ion hybrid supercapacitors (ZHSCs) are considered as compelling candidates for future energy storage. However, their practical implementation is impeded by a bottleneck due to the limited energy density of commonly used carbon cathodes. In this study, a newly designed porous carbon nanonecklace is proposed for the first time, which is developed by exquisitely threading the silk nanofibrils (SNFs) based N-doped carbon ‘nanochains’ into the metal-organic frameworks (MOFs) based N-doped porous carbon ‘nanobeads’. The necklace-like carbon/carbon structure effectively mitigates agglomeration, realizes multi-dimensional electron transport, and leads to a BET specific surface area of 1367.4 m 2  g −1 , which shows an astounding 19.6% increase in comparison to the control product (1143.5 m 2  g −1 ). When used as a cathode for ZHSCs, MPCN-150–800 exhibits a superior specific capacitance of 270.4 F g −1 , exceptional high-rate capability (57.4% capacitance retention at a 50-fold higher current density), excellent energy density of 96.1 Wh kg −1 at 159.9 W kg −1 and superb cyclic stability with 90.9% capacitance retention after 10,000 cycles at 2 A g −1 . The performance outperforms numerous counterparts fabricated so far, greatly highlighting the creative synthesis of MPCN-150–800. This work delivers a new paradigm for the design and fabrication of advanced carbon cathodes, which may boost the current state-of-the-art properties of ZHSCs.