Advancing Extreme Fast-Charging Capabilities of LiFePO₄ Using Conductive Polymer Coatings and Lithium Polyacrylate Binder

The LiFePO4 (LFP) cathode has gained commercial interest in electric vehicles (EVs) due to its cost-effectiveness and good thermal safety. With the goal of making EVs more affordable and enhancing consumer satisfaction, significantly reducing the charging time of EVs has become a critical requirement. To meet the demand for fast-charging EV batteries, while also considering environmental benefits, this work introduces a novel approach for enhancing the electrical conductivity of LFP by a combination of an aqueous binder and conductive polymers. For example, this work involved lithiated polyacrylate (LiPAA) as a binder and three different conductive polymers such as polyaniline (PANI), polypyrrole (PPy), and poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). Using only constant current (CC) charging at 5C-rate, which represents true fast-charging without using constant voltage (CV) charging mode, LFP cathodes with conductive polymers and LiPAA binder successfully achieved 85–88% of their initial capacities at 25 °C, outperforming 63% of a conventional LFP cathode with poly(vinylidene fluoride) (PVdF) binder. By creating a web-like network surrounding the active material, conductive polymers, particularly PEDOT:PSS, successfully reduced through-plane AC impedance and improved in-plane DC conductivity (by 71%) of LFP cathodes.