Three-dimensional carbon coated and high mass-loaded NiO@Ni foam anode with high specific capacity for lithium ion batteries†

Abstract

Nickel oxide (NiO) is known for its remarkable theoretical specific capacity, making it a highly appealing option for electrode materials in electrochemical energy storage applications. Nevertheless, its practical use is limited by poor electrochemical performance and complicated electrode fabrication processes. To address these issues, we propose a new anode design comprising an intermediate NiO nanoarray layer and a carbon coating layer grown directly on a three-dimensional (3D) conductive nickel foam substrate, designated as C@NiO@Ni foam. This anode with a high NiO mass loading of 5–6 mg cm⁻² is fabricated by a two-step process: thermal oxidation of the nickel foam, followed by carbon coating. The 3D architecture, with its large surface area, significantly enhances the contact between the electrode and electrolyte, thereby shortening the Li-ion diffusion pathway. Additionally, the carbon layer plays a crucial role in accommodating the volume changes of NiO during cycling, preventing the detachment of NiO from the Ni foam substrate, and enhancing the electronic conductivity of the C@NiO@Ni foam. The resulting porous C@NiO@Ni anode was thoroughly analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). When used as an anode material for lithium-ion batteries (LIBs), this anode showcased an impressive reversible capacity of around 678 mA h g⁻¹ at 0.1C after 100 cycles. Furthermore, it demonstrated excellent electrochemical performance at a high current, sustaining a specific capacity of 387 mA h g⁻¹ at 1C after 100 cycles.