Thermal Induced Strain Relaxation of 1D Iron Oxide for Solid Electrolyte Interphase Control and Lithium Storage Improvement

High energy lithium ion battery based on multi-electron redox reaction is often accompanied by inherent large volume expansions, sluggish kinetics, and unstable solid electrolyte interphase layer, leading to capacity failure. Here, thermal induced strain relaxation is proposed to realize the solid electrolyte interphase control. It is demonstrated that through thermal treatment, lattice strain is well released and defect density is well reduced, facilitating the charge transfer, improving the interparticle contacts and the contacts at the interface of electrode to withstand the huge volume expansion/contraction during cycling. In this way, the as-prepared α-Fe2O3 electrode at 800 °C with no protective shell shows an outstanding reversible capacity of 1200 mA h g−1 at 100 mA g−1 and an excellent high-rate cyclability with a capacity fading of 0.056% per cycle for 1200 cycles at 5 A g−1. It is expected that such findings facilitate the applications of high capacity anode and cathode material systems that undergo large volume expansion.