Abstract: This work investigates the beneficial roles of lithium bis(trimethylsilyl) phosphate (LiTMSP) which may act as a novel bifunctional additive for lithium ion batteries, in particular, LiNi0.5Mn1.5O4 (LNMO)/graphite cells. The cycle performance of LNMO/graphite cells is significantly improved with incorporation of LiTMSP. Trimethylsilyl functional group therein can react with HF generated through hydrolysis of LiPF6 by residual water in electrolyte solution, followed by a decrease in the concentration of metal ions dissolution from the electrode. The generation of superior passivating surface film derived by LiTMSP on graphite electrode, suppressing further electrolyte reductive decomposition and deterioration/reformation caused by migrated metal ions, is confirmed. Furthermore, LiTMSP derived surface film is likely to have better lithium ions conductivity with a decrease in resistance of the graphite electrode, improving rate performance of cells.

Abstract: Method of manufacturing lithium trifluoro(nitrato) borate as an additive for lithium-ion secondary cells, including, a) at room temperature, adding boron trifluoride complex dropwise to a solution of lithium nitrate in methanol to form a first solution, stirring the first solution overnight and removing volatile solvents in vacuo to obtain a first solid product; b) dissolving the first solid product in ester solvent, adding toluene to form a second solution, stirring the second solution overnight to obtain a white precipitate; c) decanting solvents in the second solution, drying the white precipitate in vacuo to obtain lithium trifluoro(nitrato) borate as the additive for lithium-ion secondary cells. Further disclosed is an electrolyte containing the above prepared lithium trifluoro(nitrato) borate and lithium-ion secondary cells using the electrolytes.

Abstract: This work investigates the beneficial roles of lithium bis(trimethylsilyl) phosphate (LiTMSP) which may act as a novel bifunctional additive for lithium ion batteries, in particular, LiNi0.5Mn1.5O4 (LNMO)/graphite cells. The cycle performance of LNMO/graphite cells is significantly improved with incorporation of LiTMSP. Trimethylsilyl functional group therein can react with HF generated through hydrolysis of LiPF6 by residual water in electrolyte solution, followed by a decrease in the concentration of metal ions dissolution from the electrode. The generation of superior passivating surface film derived by LiTMSP on graphite electrode, suppressing further electrolyte reductive decomposition and deterioration/reformation caused by migrated metal ions, is confirmed. Furthermore, LiTMSP derived surface film is likely to have better lithium ions conductivity with a decrease in resistance of the graphite electrode, improving rate performance of cells.