Self-standing three-dimensional porous NiO/Ni anode materials for high-areal capacity lithium storage

The low electron/ion migration rate and the high deformability of conventional two-dimensional (2D) electrodes limit the growing demand for energy storage devices with high areal capacity and stable cycling performance. Designing three-dimensional (3D) electrodes is a promising strategy to improve this defect. Herein, we prepare metallic nickel aerogel via a facile hydrothermal reduction route, which was annealed to obtain a self-standing 3D porous NiO/Ni anode. The electrode material displays a networked porous structure and good electrical conductivity, which mitigates the volume effect during cycling and provides excellent electron transport pathways and conductive ion channels. The unique structure with many electrochemical active sites performs higher areal capacity. When used as the anode of lithium-ion batteries (LIBs), a high reversible areal capacity of 1.93 mAh cm−2 is delivered at a current density of 1 mA cm−2 with a capacity retention ratio of 98.4% after 100 cycles. Remarkably, a large reversible capacity of 1.30 mAh cm−2 is also achieved at a relatively high current density of 6 mA cm−2. The 3D porous NiO/Ni anode material provides a new strategy for enhancing the energy density and stable cycling for practical application in power-type LIBs.