Close-spaced thermal 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 wildly 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 additive-free anode for LIBs. After a high-rate activation process, 3D-SSF exhibits a flatter discharge plateau than reported results and could deliver a high capacity of 471 mA h g-1 at an ultrahigh current density of 21440 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 that 3D-SFF undergoes a co-functioned 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 the homemade LiFePO4 (LFP) as the cathode.