Close-spaced thermally evaporated 3D Sb2Se3 film for high-rate and high-capacity lithium-ion storage

Abstract

As a key factor for fast-charging lithium-ion batteries (LIBs), high-rate anode materials that can recharge in a few minutes have aroused increasing attention. However, high-rate performance is always accompanied by low theoretical capacities, such as the widely known high-rate electrode of Li₄Ti₅O₁₂ (175 mA h g⁻¹), which severely limits its large-scale implementation in the development of high power density LIBs. Here, we report a modified close-spaced thermal evaporation process to deposit 3D-structured Sb₂Se₃ films (3D-SSF) with tunable morphology as an additive-free anode for LIBs. After a high-rate activation process, 3D-SSF exhibits a flatter discharge plateau than the reported results and could deliver a high capacity of 471 mA h g⁻¹ at an ultrahigh current density of 21 440 mA g⁻¹, which is superior to the widely known high-rate Li₄Ti₅O₁₂ anode (over 150 mA h g⁻¹ at 8750 mA g⁻¹). Moreover, we reveal a current-regulated Li-ion storage mechanism where 3D-SFF undergoes a synergistic conversion and alloying reaction at low current densities, while an alloying reaction-dominated process at high rates. Beyond that, full batteries with excellent rate performance were successfully assembled by pairing with homemade LiFePO₄ (LFP) as the cathode.