Ru-Doped Ni3Se4/NiSe/Nitrogen-Doped Carbon Nanotube Heterostructure for Lithium Storage

Metal–organic frameworks are widely used as anode materials for lithium-ion batteries (LIBs) because of their high specific surface areas and rich surface-active sites. However, their poor electronic conductivity and weak structural durability lead to rapid capacity fading during cycling. To solve these problems, NiRu-MOF nanotubes were templated to synthesize Ru-doped biphasic selenide nanotubes wrapped with a nitrogen-doped carbon layer (Ru–Ni3Se4/NiSe@NC). X-ray photoelectron spectroscopy and EDS tests confirm that Ru element has been successfully introduced into nanotubes. Density functional theory calculations further discover the decreased band gap and increased conductivity of Ru–Ni3Se4/NiSe@NC owing to the Ru doping effect. As the anode material for LIBs, the Ru–Ni3Se4/NiSe@NC delivers a large specific capacity of 1138 mA h g–1 at 100 mA g–1 and an excellent reversible capability of 452 mA h g–1 at 10,000 mA g–1 after 3000 cycles. The Ru–Ni3Se4/NiSe@NC//LiCoO2 full cell also presents a specific capacity of 434 mA h g–1 at 200 mA g–1 after 200 cycles. This work extends the NiRu-MOF family of materials to develop promising anode materials for high-performance LIBs.