MOF-clad FeTiO3: Synergistic suppression of material decomposition and capacity fading in lithium-ion battery anodes

Titanium iron oxide (FeTiO₃) has emerged as a promising anode material for lithium-ion batteries due to its distinctive octahedral structure, natural abundance, and high theoretical specific capacity. However, practical implementation has been hindered by significant capacity fading during cycling and structural instability under high current densities. In this study, we developed an innovative solution impregnation strategy to construct a metal-organic framework (MIL-100) protective layer on FeTiO₃ particles (denoted as FeTiO₃-MOF). This engineered architecture effectively addresses two critical challenges: (1) suppressing active material dissolution and electrode pulverization through physical confinement, and (2) enhancing charge transfer kinetics via the formation of continuous conductive pathways. The optimized FeTiO₃-MOF composite demonstrates remarkable electrochemical performance, delivering a high reversible capacity of 1077.5 mAh g⁻¹ after 150 cycles at 0.1 A g⁻¹ and maintaining 222 mAh g⁻¹ after 1000 cycles at 1 A g⁻¹ - quadruple the capacity of pristine FeTiO₃ (59 mAh g⁻¹) under identical conditions. Systematic electrochemical analysis reveals significantly improved charge transfer characteristics and lithium-ion diffusion coefficients, effectively mitigating the rapid capacity decay typically observed at elevated current densities. More importantly, this work establishes a novel self-replenishment mechanism through the rational utilization of metal ions within the MOF matrix, which dynamically compensates for active material loss during prolonged cycling. The proposed surface engineering strategy provides an effective method for developing next-generation energy storage materials that combine high capacity with exceptional cycling stability.