Electrolyte Additive cis-1,2,3,6-Tetrahydrophthalic Anhydride Enhanced the Cycle Life of Nickel-Rich LiNi_0.9Co_0.05Mn_0.05O₂

Nickel (Ni)-rich LiNixCoyMnzO2 (NCM, x ≥ 0.9) cathode materials are gaining widespread attention owing to their higher energy density than conventional cathodes, such as LiCoO2 and LiFePO4. Unfortunately, the industrial application of Ni-rich NCM materials is still restrained by the unsatisfactory electrochemical properties resulting from the unstable cathode structure and the cathode/electrolyte interface. Here, we propose an electrolyte additive, cis-1,2,3,6-tetrahydrophthalic anhydride (THPA) to enhance the interfacial stability of the Ni-rich LiNi0.90Co0.05Mn0.05O2 (NCM90) cathode. It is demonstrated that additive THPA is more preferable to be oxidized at the cathode as well as to be reduced at the anode, hindering the unwanted oxidation of carbonate solvents. An integrated and compact cathode electrolyte interphase (CEI) film is generated in the presence of a 2.0% THPA additive, mitigating the parasitic interfacial reactions, suppressing the buildup of interfacial resistance, and somewhat inhibiting the intragranular cracks. Consequently, the capacity retention of NCM90 with an electrolyte containing 2.0% THPA is boosted to 93.2% after 120 cycles at 1C (1C = 180 mA g–1) at 30 °C, well exceeding 80.0% obtained with the baseline electrolyte.