Influence of Green (TEP) Solvent on Performance of Lithium-Ion Batteries Enhanced with Novel VT475 Copolymer

The growing demand for sustainable energy storage solutions has led to an urgent need for greener manufacturing processes in lithium-ion battery (LIB) production. One of the primary environmental concerns in LIB fabrication is the use of toxic and hazardous solvents and binders in the cathode preparation process. Current cathode formulations rely heavily on N-methyl-2-pyrrolidone (NMP) as a solvent and polyvinylidene fluoride (PVDF) as a binder, both of which pose environmental and health risks. In this study, environmentally friendly solvent and various ratio binder combinations are explored, specifically Triethyl Phosphate (TEP) solvent paired with a copolymer of VT475 and PVDF at varying compositions. Blade-coated TEP, copolymer-based NMC811 cathodes were examined and compared to NMP-based ones as references. The surface morphological properties of the cathodes were analyzed using a Scanning Electron Microscope (SEM). The electrochemical performance of these green alternatives, in comparison to conventional NMP+PVDF formulations, was evaluated through a Life Cycle Test at varied C-rate charge-discharge. The results show that the TEP and copolymer-based NMC811 cathode exhibits more consistent performance compared to NMP-based ones. The TEP-based battery with 50% VT475-50% PVDF copolymer has comparable performance to the highest-performing NMP-based one in Life Cycle Testing. Additionally, TEP-based batteries with 0% VT475-100% PVDF show significantly improved performance at 5C. The findings of this research provide insight into the feasibility of greener solvent systems for LIB cathodes while maintaining or improving electrochemical performance.