Influence of component molar ratios of conjugated polymers on the anode performance in lithium-ion batteries

Abstract

Although conjugated polymers have been widely studied for their unique advantages and have shown excellent lithium storage performance, the effect of the molar ratio of their components on the electrochemical performance remains to be explored. Herein, the SFSO-1 to SFSO-5 series of conjugated polymers were synthesised by adjusting the molar ratio of each component. Among them, the SFSO-3 (m : n = 1 : 8) electrode exhibited good cycling stability (99.76% capacity retention after 1500 cycles at 0.5 A g⁻¹) and excellent rate performance (122 mA g⁻¹ reversible capacity at 1 A g⁻¹), which were related to its low charge transfer resistance (138.5 ohm) and fast Li⁺ diffusion (1.63 × 10⁻¹¹ cm² s⁻¹). Electronic conductivity and room temperature quantitative electron paramagnetic resonance (EPR) testing of polymers were also used to probe the effects of their use as electrodes. This regulation strategy of polymer electrode materials provided a new idea for the development of lithium-ion batteries (LIBs).