Influence of W-doping on electrochemical performance of spinel LiMn2O4.

ABSTRACT

The structural and electrochemical properties of W-doped LiMn2O4 and LiAl0.025Mn1.975O4 have been investigated to determine the role of W. The cathodic materials were synthesized by sol-gel method, using citric acid as the chelating agent. The results revealed that the substitution of W affects the lattice dimension, the morphology, and the electrochemical performance. Substitution of Al induces an obvious decrease in the electrochemical capacity (but higher capacity retention) and in the case of W the decrease was drastic. As observed from XRD, only a fraction of W is included in the spinel structure. However, for the LiAl0.025W0.025Mn1.95O4, a compromised value is reached between the Al-doped and W-doped LiMn2O4 in terms of capacity and cyclic performance. The pristine spinel LiMn2O4 synthesized by this method shows a relatively superior electrochemical performance at high C-rate with excellent capacity retention.