Manganese doping to boost the capacitance performance of hierarchical Co9S8@Co(OH)2 nanosheet arrays

Transition metal sulfides (TMSs) have been regarded as greatly promising electrode materials for supercapacitors because of abundant redox electroactive sites and outstanding conductivity. Herein, we report a self-supported hierarchical Mn doped Co9S8@Co(OH)(2) nanosheet arrays on nickel foam (NF) substrate by a one-step metal-organic-framework (MOF) engaged approach and a subsequent sulfurization process. Experimental results reveal that the introduction of manganese endows improved electric conductivity, enlarged electrochemical specific surface area, adjusted electronic structure of Co9S8@Co(OH)(2) and enhanced interfacial activities as well as facilitated reaction kinetics of electrodes. The optimal Mn doped Co9S8@Co(OH)(2) electrode exhibits an ultrahigh specific capacitance of 3745 F g(-1) at 1 A g(-1) (5.618 F cm(-2) at 1.5 mA cm(-2)) and sustains 1710 F g(-1) at 30 A g(-1) (2.565 F cm(-2) at 45 mA cm(-2)), surpassing most reported values on TMSs. Moreover, a battery-type asymmetric supercapacitor (ASC) device is constructed, which delivers high energy density of 50.2 Wh kg(-1) at power density of 800 W kg(-1), and outstanding long-term cycling stability (94% capacitance retention after 8000 cycles). The encouraging results might offer an effective strategy to optimize the TMSs for energy-storage devices. (c) 2021 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

A novel Mn doped Co9S8@Co(OH)2 nanosheet array electrode material was prepared by a new method, which greatly improved the capacitance and cycling stability, providing a new approach for optimizing electrode materials for supercapacitors.