Abstract
UDC 544.643-621.157
DOI https://doi.org/10.5281/zenodo.3970446
In a search of electrolytes promising for lithium batteries based on nickel sulfide electrodes, the electrochemically synthesized thin-layer NiS electrodes were studied in lithium perchlorate dissolved in 1,3-dioxolane or in a mixture of 1,3-dioxolane and tetrahydrofuran. In the electrolyte 1,3-dioxolane, 1 M LiClO4, the irreversible capacity was reduced by 20% сompared to the starting capacity. However, the stability of the electrochemical characteristics of NiS electrodes in redox reactions with lithium is unsatisfactory. Significantly improved results of charge-discharge cycling of NiS electrodes were obtained in electrolyte solutions of 1,3-dioxolane, tetrahydrofuran, and 1 M LiClO4 demonstrating a stable reversible capacity of 400–450 mAh/g during 50–75 cycles. Using the methods of electron microscopy and IR spectroscopy with Fourier transform, it was established that the reason for the discharge capacity fading of NiS electrodes was associated with the formation of a surface film, which reduces the adhesion and cohesion of NiS particles. This, in turn, leads to a loss in the mechanical strength of NiS electrodes.
Keywords: lithium batteries, NiS electrodes, electrochemical characteristics, dioxolane/LiClO4, tetrahydrofuran/LiClO4, surface films.