Improvement of the electrochemical performance of nanosized α-MnO2 used as cathode material for Li-batteries by Sn-doping

Sn-doped MnO2 was prepared by hydrothermal reaction between KMnO4 as oxidant, fumaric acid C4H4O4 as reductant and SnCl2 as doping agent. XRD analysis indicates the cryptomelane α-MnO2 crystal structure for pure and doped samples. Thermal stabilization was observed for both oxides as detected from thermogravimetric analysis. SEM and TEM images show changes in the morphology of the materials from spherical-like particles for pristine P–MnO2 to rod-like structure for Sn–MnO2. Electrochemical properties of the electrode materials have been tested in lithium cells. Improvement in capacity retention and cycling ability is observed for doped oxide at the expense of initial capacity. After 35 cycles, the Li//Sn doped MnO2 cell display lower capacity loss.

► Doping MnO2 with Sn improved properties of α-MnO2. ► Thermal stabilization and electrochemical performances were improved. ► Doping affected also the morphology feature of α-MnO2.