Porous ternary metal sulfide integrated electrode materials with abundant electroactive sites and redox reactions are very promising for supercapacitors. Herein, a porous zinc cobalt sulfide nanosheet array on Ni foam (Zn-Co-S/NF) was constructed by facile growth of 2D bimetallic zinc/cobalt-based metal-organic framework (Zn/Co-MOF) nanosheets with leaf-like morphology on NF, followed by additional sulfurization. The Zn-Co-S/NF nanosheet array acted directly as a supercapacitor electrode showing much better electrochemical performance (2354.3 F g and 88.6 % retention over 1000 cycles) when compared with zinc cobalt sulfide powder (355.3 F g and 75.8 % retention over 1000 cycles), which originates from good electrical conductivity and mechanical stability, abundant electroactive sites, and facilitated transportation of electrons and electrolyte ions due to the unique nanosheet array structure. An asymmetric supercapacitor (ASC) device assembled from Zn-Co-S/NF and activated carbon electrodes can deliver a highest energy density of 31.9 Wh kg and a maximum power density of 8.5 kW kg . Most importantly, this ASC also shows good cycling stability (71.0 % retention over 10000 cycles). Furthermore, a red LED can be powered by two connected ASCs, and thus as-synthesized Zn-Co-S/NF has great potential for practical applications.

High energy density is achieved on an electrode based on ultrathin Ni-MOF nanosheet arrays grown on PANI decorated NF.

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In this work, a hierarchical 2D polyaniline (PANI)/Ni3S2 nanosheet arrays on Ni foam (NF) with open network was successfully developed by the growth of Ni3S2 nanosheet arrays derived from 2D Ni−MOF templates followed by the electrodeposition of a layer of PANI nanoflakes. The as‐prepared PANI/Ni3S2/NF was served as self‐standing supercapacitor electrode. The optimized PANI/Ni3S2/NF‐100 electrode exhibits a high areal capacity of 1.56 mA h cm−2 (487.5 mA h g−1) at 5 mA cm−2 and good rate capability (57.7 % retention at 50 mA cm−2), which significantly outperforms individual PANI/NF or Ni3S2/NF. Furthermore, an asymmetric supercapacitor fabricated by PANI/Ni3S2/NF‐100 and activated carbon electrodes can deliver a high energy density of 48.3 W h kg−1 at a power density of 799.8 W kg−1 with outstanding durability (85.7 % retention of the initial capacity) during 15000 consecutive charge‐discharge cycles. The superior electrochemical performance of PANI/Ni3S2/NF‐100 is attributed to the unique hierarchical PANI/Ni3S2 nanosheet arrays structure. Firstly, the hierarchical open network facilitates the electrolyte ions transport. Secondly, the ultrathin 2D Ni3S2 nanosheets lead to abundant electroactive sites for the Faradaic process, and the conductive PANI layer builds superb highway for fast electron transfer. Thirdly, the free‐standing electrode enables fast redox reaction and low interfacial resistance. Finally, the synergetic effect of Ni3S2 and PANI also contributes to the enhanced capacity.