De-lithiation polarization enhanced tungsten oxide/carbon composite-based highly reversible negative electrode for lithium-ion batteries

Tungsten oxide-carbon composite (WO
₃
-C) is synthesized and applied as the negative electrode for lithium-ion batteries. The conversion reaction of WO
₃
to W
⁰
and Li
₂
O is major lithiation mechanism of WO
₃
-C. GITT analysis shows the distinguishable advance at de-lithiation resistance of tungsten oxide from composite electrode. This enhancement of polarization is from the high electric conductivity of carbon structure and the reduction of particle size. The decrease of de-lithiation polarization leads the WO
₃
-C electrode to very stable cycleability, which is not generally expected from the typical conversion type negative electrodes.