Abstract:
A novel zwitterionic lithium-benzotriazole sulfobetaine is fabricated by grafting 1,3– propanesultone onto
benzotriazole and then lithiating it. The resultant lithium-benzotriazole-sulfobetaine additive is used as an
electrolyte additive in lithium ion batteries in 1M LiPF6 (ethylene carbonate/dimethyl carbonate=1:1). The
electrolytes with the lithium-benzotriazole sulfobetaine shows higher ionic conductivities (2.18 × 10−2 S cm−1)
compared to the bare electrolyte (1.07 × 10−2 S cm−1) and greater electrochemical stability (anodic limit at
~5.5 V vs. Li/Li+) than the pure electrolyte (anodic limit at ~4.6 V vs. Li/Li+). The discharge capacity of the
lithium cobalt oxide/graphite cells is improved at higher C-rates with the addition of lithium-benzotriazole
sulfobetaine due to increased ionic conductivity. The lithium cobalt oxide/graphite cells with the lithiumbenzotriazole
sulfobetaine additive also show stable cycling performance. These findings warrant the use of
lithium-benzotriazole sulfobetaine as an electrolyte additive in lithium ion batteries.
