Investigation of an eco‐friendly polyacrylic acid binder system on LiFePO4 cathode electrode processing to enhance the performance of coin‐cell and pouch‐cell graphite||LiFePO4 batteries

Abstract

AbstractThis study investigates the influence of two types of binders (aqueous and nonaqueous) on the LiFePO4 (LFP) electrode processing and its electrochemical properties. Specifically, polyvinylidene fluoride (PVDF) and polyacrylic acid (PAA) were dissolved in NMP (N‐methyl‐2‐pyrrolidone) or the aqueous solvent (H2O) at varying mass ratios of 5%, 10%, and 15%. Binder durability and inertness were assessed by immersing prepared LFP electrodes in an electrolyte comprising 1.0 M LiPF6 in EC:DEC:DMC (1:1:1 in vol%). Notably, PVDF/NMP 10% and PAA/H2O 10%‐based electrodes displayed good durability without peeling. Electrochemical characteristics were evaluated through cycling voltammetry and galvanostatic cycling with potential limitation. The PAA/H2O 10%‐based‐LFP electrode exhibited a specific capacity of ~148.9 mAh g−1 with a Coulombic efficiency (CE) of around 97.27%, surpassing PVDF/NMP 10%. The graphite||PAA/H2O 10%‐based‐LFP electrode in a full cell demonstrated higher capacity and superior retention after 30 cycles. In a pouch cell (6 cm × 4 cm), utilizing graphite||LFP with PAA/H2O 10%, a capacity of 25.5 mAh was achieved, maintaining 93% capacity with a CE of about 99% after 30 cycles at a rate of 0.1C.