Enhanced adhesion in PTFE-based dry electrodes with hydrogen bonding co-binder integration for advanced lithium-ion batteries

Abstract

As the demand for sustainable energy solutions grows, dry electrode manufacturing processes have gained attention for their energy efficiency and elimination of harmful solvents compared to conventional methods. However, polytetrafluoroethylene (PTFE), a widely used binder in dry electrodes, suffers from poor adhesion to current collectors, resulting in high contact resistance and rapid capacity degradation. To address these limitations, this study introduces polyacrylic acid (PAA) as a hydrogen-bonding co-binder. The combination of PAA and PTFE significantly enhanced adhesion strength (40.0 gf·20 mm⁻¹ compared to near-zero for PTFE alone) and reduced interfacial resistance, ensuring stable electrode performance. Electrochemical evaluations demonstrated that PAA/PTFE electrodes exhibit superior rate capability and cycling stability. In full-cells, the PAA/PTFE binder system achieved an initial discharge capacity of 197.9 mAh·g⁻¹ at 0.1C and a capacity retention of 82.2 % after 300 cycles at 1C, outperforming conventional PTFE-based systems (63.5 %). Furthermore, the improved cohesion within the electrode structure and enhanced wettability with the electrolyte contributed to the superior performance. These findings highlight the potential of PAA/PTFE as a scalable and sustainable solution for advancing dry electrode technologies, paving the way for efficient and eco-friendly lithium-ion battery production.