Abstract: This study systematically evaluates the impact of combining the water-based binder polyacrylic acid (PAA) with different types of styrene-butadiene rubber (SBR) on the performance of lithium-ion batteries. By maintaining a fixed PAA content while varying the SBR type, the research analyzes their effects on anode characteristics and full-cell electrochemical performance, and further investigates the influence of increasing the PAA content on the performance evolution of electrodes and cells. The results indicate that the combination of lithiated SBR (SBR-Li) with PAA synergistically achieves both low electrode impedance and excellent electrolyte wettability. Electrochemical tests demonstrate that using small-particle-size, high-modulus SBR-Li reduces the cell's AC impedance (ACR) and DC internal resistance (DCR), increases the constant current ratio in 1C charging by 2.4%, and improves the capacity retention rate by approximately 1% after 500 cycles at 25°C. However, when the PAA content is increased by 0.5%, cell impedance rises and rate capability weakens, although the cycle swelling rate decreases by 0.5%. This study demonstrates that the formulation of lithiated SBR and PAA can selectively tune the performance of silicon-based battery systems, providing crucial guidance for binder selection in silicon-based material applications.

Key words: Lithium-ion battery, Silicon anode, PAA, SBR-Li