Solvent-controlled synthesis of mesoporous CoO with different morphologies as binder-free anodes for lithium-ion batteries

The solvent-controlled synthesis of mesoporous CoO with different morphologies was investigated through a facile route including hydrothermal reaction and subsequent calcination. By altering the solvent of reaction, CoO nanowires (CoO-NWs) and CoO polyhedron (CoO-PHn) were favorably loaded on nickel foam with robust adhesion. Compared with CoO-PHn, CoO-NWs for lithium storage has enhanced electrochemical performance in term of high reversible capacity and extraordinary rate capability. After 80 cycles, an outstanding reversible specific capacity for CoO-NWs was 1398 mA h/g at a current density of 200 mA/g. Furthermore, a reversible specific capacity was up to 1175 mA h/g even at a current density of 1000 mA/g. The extraordinary electrochemical property was owing to the presence of free voids, which significantly buffered the mechanical stress during the insertion/de-insertion process. In addition, one-dimensional (1D) morphology ensured a relatively short transmission route to accelerate electron transport.