Improvement of the characteristics of poly(acrylonitrile–butylacrylate) water-dispersed binder for lithium-ion batteries by the addition of acrylic acid and polystyrene seed

• A new water-dispersed binder is developed for lithium-ion battery anodes.
• Poly(acrylicacid–acrylonitrile–butylacrylate)–polystyrene binder, P(AA–AN–BA)–PS.
• The binder remains strongly adhered even after soaking in the electrolyte.
• P(AA–AN–BA)–PS binder significantly improves the performance of high-capacity anodes.

In this study, we modified an attractive water-dispersed poly(acrylonitrile–butylacrylate) binder used for lithium-ion batteries by the addition of highly acidic acrylic acid (AA). The synthesized poly(acrylicacid–acrylonitrile–butylacrylate)–polystyrene polymer showed an improved performance as a binder with smaller particle size, stiffer polymer matrix, higher adhesion strength, and lower contact angle characteristics. Consequently, the modified water-dispersed binder by the addition of AA increased the cyclic capacity and retention of physically mixed silicon/graphite anodes, when compared to the unmodified poly(acrylonitrile–butylacrylate) binder.