In Situ Encapsulation of Germanium Clusters in Carbon Nanofibers: High‐Performance Anodes for Lithium‐Ion Batteries

Abstract Alloyed anode materials for lithium‐ion batteries (LIBs) usually suffer from considerable capacity losses during charge–discharge process. Herein, in situ‐grown germanium clusters are homogeneously encapsulated into porous nitrogen‐doped carbon nanofibers (N‐CNFs) to form Ge/N‐CNFs hybrids, using a facile electrospinning method followed by thermal treatment. When used as anode in LIBs, the Ge/N‐CNFs hybrids exhibit excellent lithium storage performance in terms of specific capacity, cycling stability, and rate capability. The excellent electrochemical properties can be attributed to the unique structural features: the distribution of the germanium clusters, porous carbon nanofibers, and GeN chemical bonds all contribute to alleviating the large volume changes of germanium during the discharge–charge process, while at same time the unique porous N‐CNFs not only increase the contact area between the electrode and the electrolyte, but also the conductivity of the hybrid.