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

• A novel sand-like electrolyte is prepared.
• The anodic stability of sand-like electrolyte is superior in the presence of Li2SiO3.
• Cycling stability of 5 V LiNi0.5Mn1.5O4 is enhanced.
• Intensive electrolyte oxidation is supressed during cycling under high potential.
• Li2SiO3 can consume the PF5 and HF in electrolyte.

The electrochemical performance of LiNi0.5Mn1.5O4 is investigated in a sand-like carbonate electrolyte containing 4 wt.% lithium metasilicate (Li2SiO3). The capacity fading rate of the LiNi0.5Mn1.5O4 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.

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