Enhanced electrochemical properties of LiMn2O4 cathode material coated by 5 wt.% of nano-La2O3

Spinel LiMn2O4 was synthesized by solid state reaction. 5.0 wt.% of La2O3 was coated on the surface of LiMn2O4 via ball-milling method, followed by calcination at 650 °C for 5 h in the air. The uncoated and La2O3-coated LiMn2O4 materials were physically characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area measurements. It was observed that Li/LiMn2O4 electrode obtained the capacity retention of 76.7% after 205 cycles at 1 C rate at 25 °C while that of the coated sample was 90.1%. At 55 °C, the bare and coated LiMn2O4 showed a capacity retention of 69.4% and 82.6% after 95 cycles, respectively. Rate capability was also improved. The capacity retention of uncoated and La2O3-coated materials reduced to 46.9% and 80.3% at 10 C-rate, respectively.

► Nano-La2O3 (5.0 wt.%) coated LiMn2O4 has been synthesized via ball-milling method. ► TEM images indicate that La2O3 layer was formed over the bare LiMn2O4 powder. ► The La2O3-coated LiMn2O4 exhibited an excellent capacity retention. ► Rate capability of the La2O3-coated LiMn2O4 was also improved.