Improving electrochemical performance of a high-voltage LiNi0.5Co0.2Mn0.3O2 cathode through interfacial stabilization using curcumin as a novel electrolyte additive

The current investigation focused on evaluating the potential of Curcumin as neoteric bio-based additive for lithium ion batteries electrolyte to enhance the cycling behavior of LiNi_0.5Co_0.2Mn_0.3O₂ cell at 4.4 V (vs Li/Li⁺) charging cut-off voltage. Inclusion of 0.04-wt% Curcumin to the carbonate electrolyte resulted in a tremendous enhancement on the cycling performance with the capacity retention of 91% after 100 cycles, while it was only 79% for pristine electrolyte. According to the density functional theory (DFT) calculations, it has been found that Curcumin possesses a higher energy level for its highest occupied molecular orbital (HOMO) and exhibits a lower oxidation potential when compared to carbonate solvents. These results indicate that Curcumin undergoes oxidation decomposition prior to the electrolyte solvents, thereby creating a protective cathode electrolyte interphase (CEI) on NCM. This observation is in line with the results obtained from the linear sweep voltammetry (LSV) analysis. The effects of Curcumin were examined using various electrochemical and physical techniques, including linear sweep voltammetry (LSV), cyclic voltammetry (CV), charge/discharge test, electrochemical impedance spectroscopy (EIS), field emission scanning and transmission electron microscopy (FESEM, TEM), X-ray diffraction spectroscopy (XRD) and X-ray photoelectron spectroscopy (XPS). The findings demonstrated that the enhanced battery performance is related to the construction of a thinner film on NCM facilitated by Curcumin, which led to reduced interfacial impedance and inhibit the degradation of carbonate electrolyte at higher charging cut-off voltage.