Modified electrochemical performance of high potential cathode using a sand-like carbonate electrolyte

The electrochemical performance of LiNi_0.5Mn_1.5O₄ is investigated in a sand-like carbonate electrolyte containing 4 wt.% lithium metasilicate (Li₂SiO₃). The capacity fading rate of the LiNi_0.5Mn_1.5O₄ electrode working in the sand-like electrolyte (2-5 V) is reduced to 0.171 mAh g^-1 per cycle, quite smaller than the value of 0.613 mAh g^-1 per cycle in the electrolyte without Li₂SiO₃. The capacity of 159.5 mAh g^-1 is delivered at 0.5 C after 118 cycles while it is only 99.4 mAh g^-1 for the Li₂SiO₃-free counterpart. Cyclic voltammetry, scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopic measurements are conducted to explore the modification mechanism. It is found that the anodic stability of the sand-like electrolyte is improved compared to the base electrolyte. The Li₂SiO₃ precipitates on the electrode surface make contribution to the performance enhancement of the cathode at high potential.