Improvement of the electrochemical performance of LiMn2O4 cathode active material by lithium borosilicate (LBS) surface coating for lithium-ion batteries

The LBS coating on the surface of spinel LiMn2O4 powder was carried out using the solid-state method, followed by heating at 425 °C for 5 h in air. The powder X-ray diffraction pattern of the LBS-coated spinel LiMn2O4 showed that the LBS coating medium was not incorporated in the spinel bulk structure. The SEM result showed that the LBS coating particles were homogeneously distributed on the surface of the LiMn2O4 powder particles. The effect of the lithium borosilicate (LBS) coating on the charge–discharge cycling performance of spinel powder (LiMn2O4) was studied in the range of 3.5–4.5 V at 1C. The electrochemical results showed that LBS-coated spinel exhibited a more stable cycle performance than bare spinel. The capacity retention of LBS-coated spinel was more than 93.3% after 70 cycles at room temperature, which was maintained at 71.6% after 70 cycles at 55 °C. The improvement of electrochemical performance may be attributed to suppression of Mn2+ dissolution into the electrolyte via the LBS glass layer.

Research highlights▶ The LiMn2O4 cathode was successfully coated with LBS using tetraethylorthosilicate, boric acid and lithium nitrate as the precursor. ▶ To improve the electrochemical performance of LiMn2O4 cathode material, the LBS coating is an effective way. ▶ Coating the spinel LiMn2O4 with LBS glass layer resulted in a tremendous improvement in retention of capacity at room and elevated temperature. ▶ The capacity retention of the LBS-coated LiMn2O4 over 70 cycles was 93.3% and 71.6%, while pristine showed 74.6% and 53% capacity retention of the initial discharge capacity at room and elevated temperature, respectively.