Advancing Extreme Fast-Charging Capabilities of LiFePO4 Using Conductive Polymer Coatings and Lithium Polyacrylate Binder,
ACS Applied Energy Materials
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.