Construction and modification of germanium-based anode materials in lithium-ion batteries

Lithium-ion batteries have been widely used in portable electronic devices and electric vehicles due to their high energy density, long cycle life, and no memory effect. Germanium-based anode materials have emerged as a key focus of research in the realm of lithium-ion batteries, owing to their high theoretical specific capacity (about 4 times that of carbon), low lithium insertion potential, and excellent conductivity (about 104 times that of silicon). In recent years, researchers have conducted extensive studies on the synthesis and modification of germanium-based anode materials, resulting in significant breakthroughs. However, germanium-based anode materials still have many challenges in terms of cycling stability, which is mainly due to the serious volume effect and unstable interface during the charge and discharge processes. In this paper, we introduce the preparation methods, morphology, structure, and electrochemical properties of diverse germanium-based anode materials through the four modification strategies: low-dimensional nanostructuring, three-dimensional heterogeneous structure construction, germanium-carbon composite, germanium alloying. Finally, the research progress on modification methods and approaches for germanium-based anode materials is discussed, along with future research directions.