Electrodeposition of conductive polymer PEDOT on the surface of the LiNi0.8Co0.1Mn0.1O2 electrode for high-performance lithium-ion batteries

Abstract

Although high-nickel cathode materials LiNi_1−x−yCo_xMn_yO₂ (1 − x − y ≥ 0.6, NCM) have high energy density and low cost, they undergo multiple phase transitions during the charge and discharge processes, leading to material cracks and particle pulverization, thereby detaching from the aluminum foil current collector. Herein, a flexible conductive polymer poly(3,4-ethoxythioene) (PEDOT) is electrodeposited onto the LiNi_0.8Co_0.1Mn_0.1O₂ cathode electrode. PEDOT is uniformly coated on the cathode material and aluminum foil, acting as a binder it improves adhesion. It also minimizes side reactions between the cathode material and the electrolyte, boosting charge transfer on the electrode surface. Consequently, the interface impedance and charge transfer impedance of the modified electrode decreased from 35.76 and 35.91 Ω to 17.11 and 19.58 Ω, respectively. After 100 cycles at 1C rate within the voltage range of 2.8–4.3 V, the discharge specific capacity of the PEDOT-coated electrode decreases from 177.8 mA h g⁻¹ to 155.2 mA h g⁻¹ with a capacity retention rate of 87.28%, which is significantly higher than 72.74% of the original electrode.