The design of novel lithium salt additives: 4-benzonitrile-1,3-double (trimethylboric acid) lithium (LBTA) to endow inherent superior stability in high voltage lithium ion batteries

Abstract

Noted that electrolyte additives containing either B-O groups or nitrile groups are being capable of lifting battery capacity, but there is little literature on the ability to combine the advantages of both B-O groups and nitrile groups to jointly contribute to the capacity enhancement for NCM811-based lithium-ion batteries. Therefore, in the current work, a novel Lithium salt 4-benzonitrile-1,3-double (trimethylboric acid) lithium (LBTA) additive including two types groups (B-O and nitrile groups) is designed as a interface film promoter existed between the electrolyte and electrodes mainly to boost electrochemical performance in lithium-ion batteries under the high-voltage conditions. The results show that the capacity of the battery improve from 94.4 mAh g⁻¹ to 162.2 mAh g⁻¹ after 200 cycles at 4.5 V by adding 0.03 LBTA to the conference (1 mol/L LiPF₆ with the solvent: DMC: EMC: EC = 1:1:1, vot. %). Further investigation of the mechanism for the capacity enhancement of the battery evidenced via characterization and computational methods showed that LBTA can preferentially sacrifice on the the electrodes’ surface over other carbonate solvents to form a more stable and dense passivation layer, which derived from decomposition of LBTA can better stable electrodes’ microstructure and alleviate the decomposition of state-of-the-art batteries electrolytes, subsequently enhancing the stability of the rechargeable battery in the high-voltage conditions.