Secondary Battery Electrolyte Composition for Cycle Life

The patent modifies the chemical composition parameters of the electrolyte by introducing specific compounds (sulfone compounds of Formula (1) and (2), nitrile compounds, and isocyanate compounds of Formula (3) and (4)) with controlled amounts (0.01-5 wt% for sulfone compounds, 0.01-10 wt% for nitrile compounds, 0.01-5 wt% for isocyanate compounds). These parameter changes enhance the electrolyte's chemical stability during charge-discharge cycles while maintaining high energy density, directly resolving the contradiction between reliability and compositional stability.

The patent creates a composite electrolyte system by combining multiple types of compounds: sulfone compounds (Formula (1) and (2)), nitrile compounds, and isocyanate compounds (Formula (3) and (4)) with conventional electrolyte components. This composite approach synergistically improves cycle characteristics through the combined effects of these compounds in suppressing electrolyte decomposition, while maintaining the high energy density properties of the base electrolyte system.

The patent applies preliminary action by incorporating specific protective compounds (sulfone, nitrile, and isocyanate compounds) into the electrolyte composition before the battery is put into service. These compounds pre-establish a stable chemical environment that prevents decomposition during subsequent charge-discharge cycles, thereby extending operational life while maintaining reliability from the first cycle onward.

The patent converts the potentially harmful effect of repeated charge-discharge cycles (which cause electrolyte decomposition) into a beneficial outcome by using specific compounds that not only resist decomposition but also improve cycle characteristics. The sulfone, nitrile, and isocyanate compounds transform the stress of repeated cycling into an opportunity to demonstrate enhanced stability and extended battery life.