Facile method to improve initial reversible capacity of hollow carbon nanofiber anodes

A facile method is developed to improve the initial reversible capacity of hollow carbon nanofibers (HCNFs), which are manufactured via coaxial electrospinning of core/shell precursor nanofibers and their thermal treatments for stabilization and carbonization. Since the low initial reversible capacity of HCNFs is mainly caused by mesopores in the HCNFs, in our approach, the size of these mesopores is reduced by simply introducing a chemical vapor deposition (CVD) process between the stabilization and carbonization processes, thereby inducing the deposition of carbon atoms in the mesopores. The initial coulombic efficiencies of the HCNFs and the Si-encapsulated HCNFs are significantly increased by employing CVD process. The mechanism behind such improvement is revealed by morphological, microstructural, surface, and electrochemical analyses, confirming that control of the mesopores in HCNFs is an effective means to improve the electrochemical performance of HCNFs.