Preparation of three-dimensional compressible MnO₂@carbon nanotube sponges with enhanced supercapacitor performance

Fabrication of highly durable and compressible electrode materials for supercapacitors has been vital to promote the use of elastic electronics and deformation-tolerant devices. Here, a novel three-dimensional (3D) nanocomposite of a compressible MnO₂@carbon nanotube (CNT) sponge has been synthesized via the in situ chemical reaction without complicated processing for compressible supercapacitor electrodes. The 3D porous, compressible structure and good mechanical properties make melamine foam an ideal substrate for highly electrically conductive CNTs, which permits fabrication of a compressible 3D conductive network. The specific capacitance can be further improved by introducing the pseudocapacitive material MnO₂. As a result, the MnO₂@CNT sponge nanocomposite exhibits a high specific capacitance of 600 F g^-1 at 1 A g^-1 coupled with good rate capability (430 F g^-1 at 10 A g^-1). In addition, high electrochemical performances are well maintained under a high compressive strain of 80%. This facile method provides an available strategy for designing and fabricating good performance compressible supercapacitor electrodes.