β-phase polymer-driven enhanced powder flowability and microstructure uniformity for stable and fast dry-processed electrode

Abstract

The development of high-energy-density lithium-ion batteries (LIBs) requires a scalable architecture featuring a thick, high-mass-loading cathode without compromising electrochemical performance. However, conventional slurry-based processes struggle to achieve structural uniformity owing to carbon-binder domain (CBD) migration in thick, high-mass-loading systems, resulting in nonuniform electrochemical reactions within the electrode. This study aims to introduce a versatile copolymer, poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE), as a functional binder optimized for the dry manufacturing process. This binder facilitates uniform electrode fabrication through the robust flow characteristics of the dry process while ensuring electrochemical homogeneity via spontaneous beta (beta)-phase formation, an intrinsic dipole network, and ferroelectric properties. The resulting electrodes exhibit a pronounced dielectric response and efficient electrochemical kinetics at 1 C, even with a high active material loading of up to 62 mg cm- 2. Furthermore, X-ray-based post-mortem analyses clearly confirm the homogeneous electrochemical behavior and reversibility of the thick electrode. The full cell paired with a graphite anode delivers stable capacity retention of 71.3 % after 750 cycles, demonstrating the long-term cycling stability of the dry thick electrode and critical effectiveness of the functional binder in enhancing electrode fabrication and electrochemical durability.