Encapsulating hetero-Cu3Ge/Ge into nitrogen-doped carbon matrix for advanced lithium storage

The traditional graphite anode with a specific capacity of 372 mA h g −1 for lithium-ion batteries (LIBs) can’t satisfy the increasing demands of energy density . Germanium (Ge) anode material has been considered as a promising candidate owning to its higher theoretical specific capacity (∼1600 mA h g −1 ). Unfortunately, lithiation/delithiation process of Ge produces a huge volume variation, resulting in poor electrochemical performances. Herein, we designed and prepared a unique Ge-based composite that immersing hetero-Cu 3 Ge/Cu into a nitrogen-doped carbon matrix (CG/G@NC). In this delicate architecture, both NC and electrochemically inert Cu 3 Ge act as conductive additives and volume buffers to improve conductivity and mitigate volume changes, respectively. Also, heterostructure possesses good charge transfer kinetics and offers an additional Li + diffusion path. As result, the Li + diffusion in CG/G@NC composite is ∼930 times as fast as commercial Ge and ∼320 times as fast as NC. As expected, the as-prepared CG/G@NC composite exhibits superior outstanding cycle stability (455 mA h g −1 after 500 cycles at a constant current density 1000 mA g −1 ) and exceptional rate capability. Meaningfully, encapsulating Ge-based heterostructure materials with functional components into the carbon matrix is a promising method to facilitate the practical application of Ge-based anode materials.