Alternating Current−Electrophoretic Deposition-Assembled Metal−Organic Framework-Derived LiFePO ₄ Composite Films: Robust Redox Kinetics in Binder- and Carbon Black-Free Electrodes

Eliminating inactive components in electrode formulations is a critical pathway toward an intrinsic property-revealing platform. In this work, we report the fabrication of a binder- and conductive agent-free LiFePO4 (LFP) cathode via alternating current electrophoretic deposition (AC-EPD). Using a metal−organic framework (MOF)-derived synthesis strategy, we developed LFP microparticles encapsulated in an MOF-derived carbon with possible residual oxygen-containing functionalities, facilitating both the electrophoretic assembly and electrochemical charge transfer without extrinsic additives. The resulting electrode forms a thin, uniform architecture with a thickness of less than 3 μm and a mass loading of ∼0.3 mg cm−2. Structural characterization confirms a high-purity olivine LFP phase and retention of the polyhedral morphology derived from the Fe-MOF precursor. Electrochemically, the additive-free cathode delivers a stable reversible capacity of approximately 75 mAh g−1 at 1 C, with predictable rate-dependent decreases at higher current densities and strong reversibility upon returning to lower rate. Rather than targeting a practically optimized high-loading cathode, this study establishes an ultrathin additive-free model architecture for clarifying the intrinsic redox kinetics and interfacial evolution of MOF-derived LFP. The combined electrochemical and structural results show that AC-EPD enables direct assembly of a binder-free electrode in which additive-induced artifacts are minimized, thereby providing a simplified platform for investigating transport behavior and contact stabilization in MOF-derived cathode materials.