General Formation of M x Co 3− x S 4 (M=Ni, Mn, Zn) Hollow Tubular Structures for Hybrid Supercapacitors

A simple and versatile method for general synthesis of uniform one‐dimensional (1D) M x Co 3− x S 4 (M=Ni, Mn, Zn) hollow tubular structures (HTSs), using soft polymeric nanofibers as a template, is described. Fibrous core–shell polymer@M‐Co acetate hydroxide precursors with a controllable molar ratio of M/Co are first prepared, followed by a sulfidation process to obtain core–shell polymer@M x Co 3− x S 4 composite nanofibers. The as‐made M x Co 3− x S 4 HTSs have a high surface area and exhibit exceptional electrochemical performance as electrode materials for hybrid supercapacitors. For example, the MnCo 2 S 4 HTS electrode can deliver specific capacitance of 1094 F g −1 at 10 A g −1 , and the cycling stability is remarkable, with only about 6 % loss over 20 000 cycles.