Realizing reversible conversion-alloying of GeO2/N-doped carbon nanocomposite with oxygen vacancies for lithium-ion batteries

A new nanocomposite of GeO 2 /nitrogen-doped carbon (GeO 2 /NC) with abundance oxygen vacancies has been synthesized based on a reaction induced by a cationic surfactant and not only exhibits a superb rate performance and favorable cycling stability but also displays an ultrahigh reversible capacity when served as an anode for lithium ion batteries . Such an excellent performance can be associated with the highly enhanced kinetics in conversion reaction, which is derived from the synergistic effects among the unique N-doped carbon layer, GeO 2 nanoparticles , and oxygen vacancies. Driven by the overwhelming advantages, the GeO 2 /NC nanocomposite delivers a large capacity of 1044.6 mA h/g at 1.0 A/g even after 1200 cycles with negligible capacity attenuation and superb reversibility, in which a Coulombic efficiency is over 99.6%. Furthermore, the electrochemical reaction mechanism is also revealed by the in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy, and confirming that the conversion reaction is highly reversible even after 1200 cycles.