An ultra-high-performance anode material for supercapacitors: self-assembled long Co3O4 hollow tube network with multiple heteroatom (C-, N- and S-) doping

Three unique morphologies of heteroatom (C-, N- and S-) self-doped Co3O4 network structures of super-long hollow tubes have been produced by hydrothermal and calcination techniques using the chicken eggshell membrane as the template and dopant. The obtained Co3O4 shows a super high specific capacitance (1498 F g(-1) at a current density of 0.5 A g(-1)), and a good rate capability (795 F g(-1) at a high current density of 10 A g(-1)). Furthermore, the assembled asymmetric supercapacitor delivers a high energy density of 29.5 W h kg(-1), as well as excellent long-term cyclic stability (91.4% capacitance retention over 1000 cycles). It is speculated that the synergistic effect of long hollow network tubes and trace amounts of heteroatom doping contributes to the remarkable electrochemical performance.