Anion engineering in lithium cobalt oxide for application in high-performance supercapacitors

This study has focused on enhancing the effectiveness of supercapacitors, which are crucial for energy storage applications. Traditionally, supercapacitors have faced challenges in achieving higher energy density than batteries. This study hypothesizes that modifying the anionic structure of lithium cobalt oxide can significantly improve supercapacitors' energy density and charge storage capability. Lithium cobalt oxide was synthesized by sol-gel method, and LiCoO_2-x(F_0.8Cl_0.2)_x with x = 0.1, 0.2, and 0.4 (F = 0.8x, Cl = 0.2x), was obtained by anion-exchange method. The structure and crystalline nature of the synthesized samples were analyzed using Fourier-transform infrared spectroscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy. To further confirm the correctness of the structures, microstructural and morphological studies were conducted using Field emission scanning electron microscopy and Transmission electron microscopy. The charge-discharge investigations showed that the electrode made of LiCoO_1.6(F_0.8Cl_0.2)_0.4 had a high specific capacitance (522.16 F g^-1 at a current density of 1 A g^-1) compared to the Lithium Cobalt Oxide electrode. In addition, it showed a fabulous cycle life stability with 92.04% coulombic efficiency after 4000 charge-discharge cycles.