The electrochemical reaction mechanism of germanium with lithium at room temperature was investigated. Two distinct voltage plateaus corresponding to the formation of and were observed, and the final products were identified as a mixture of and phases. A three-step reaction mechanism of germanium with lithium was suggested. Carbon-coated germanium composites prepared by mechanical milling and pyrolysis were evaluated as anode materials for lithium-ion batteries. The composite materials, Ge–mesocarbon microbeads and Ge–poly(vinyl alcohol), showed good cyclability and retained fairly large capacities of 473 and , respectively, up to 50 cycles when cycled within a limited voltage window.

Niobium-based oxides are considered promising anode materials for Li-ion batteries due to their high capacities, good cyclability, and excellent safety. Here, CuNb₂O₆, ZnNb₂O₆, and MnNb₂O₆ niobate nanoparticles were prepared using a solvothermal method followed by heat treatment, and their electrochemical properties as anode materials for Li-ion batteries were explored. These CuNb₂O₆, ZnNb₂O₆, and MnNb₂O₆ nanoparticles have BET surface areas of 3.17–11.53 m² g⁻¹. As anode materials, these nanoparticles display high reversible capacities of 256, 309, and 352 mA h g⁻¹, respectively, at C/10; in particular, the excellent capacity retention rates of the CuNb₂O₆ nanoparticle sample at 5C and 10C are 158 and 131 mA h g⁻¹, respectively. After the first cycle, the Li-ion diffusion coefficients lie between ∼1.6 × 10⁻⁷ and ∼2.1 × 10⁻¹⁰ cm² s⁻¹, which effectively promotes Li-ion uptake. Ex situ X-ray diffractometry provides insight into the insertion reaction by monitoring the changes in the crystal structures of the niobate samples during charge–discharge processes. We demonstrate that these niobate nanoparticle samples are possible alternative anode materials for use in rechargeable batteries.