Electrodeposition of manganese oxide and poly(s-triazine) composites for aqueous electrochemical energy storage

Electrodeposition offers a facile route in constructing metal oxide/conducting polymer composites on conductive substrates. Here, manganese oxide/poly(s-triazine) composites (MnO_x/PT) are simultaneously electrodeposited on carbon cloth substrate using a galvanostatic method. The specific capacities of MnO_x/PT are 140.44 and 213.48 mAh g^-1 in 1 M Na₂SO₄ and 2 M (NH₄)₂SO₄, respectively, at 1 A g^-1 charging-discharging current density. Compared to MnO_x and PT, the MnO_x/PT exhibits higher specific capacity and cyclic stability owing to its higher number of active sites, lower charge transfer resistance and more facile ion diffusion. An aqueous electrochemical energy storage device is assembled with two MnO_x/PT and 2 M (NH₄)₂SO₄, and the specific capacity reaches 61.71 mAh g^-1 at 1 A g^-1. A 163 Wh kg^-1 specific energy density at a specific power density of 540 W kg^-1 is exhibited. In addition, the device also shows good cycling stability with 82.16% capacity retention after 3000 cycles.