Thin solid electrolyte interface on chemically bonded Sb2Te3/CNT composite anodes for high performance sodium ion full cells

Publication date: Available online 14 February 2020Source: Nano EnergyAuthor(s): Muhammad Ihsan-Ul-Haq, He Huang, Junxiong Wu, Jiang Cui, Shanshan Yao, Woon Gie Chong, Baoling Huang, Jang-Kyo KimAbstractNanostructured metal chalcogenides (MCs) and their composites are studied for high performance sodium-ion batteries (SIBs). Herein, we report the assembly of an emerging MC, Sb2Te3, with functionalized carbon nanotubes (CNTs) to form composite anodes. The role of oxygenated functional groups on CNTs in fostering the chemical interactions with Sb2Te3 for enhanced structural integrity of electrodes is elucidated by density functional theory combined with ab-initio molecular dynamics simulations and X-ray photoelectron spectroscopy analysis. Remarkably, cryogenic transmission electron microscopy (TEM) analysis reveals a uniform and thin solid electrolyte interface (SEI) layer of ∼19.1 nm on the Sb2Te3/CNT composite while the neat Sb2Te3 presents an irregular and ∼ 67.3 nm thick SEI. The ex-situ X-ray diffraction (XRD) and ex-situ/in-situ TEM analyses offer mechanistic explanations of phase transition and volume changes during sodiation. The Sb2Te3/CNT composite electrode with an optimal content of 10 wt.% CNTs delivers excellent reversible gravimetric and volumetric capacities of 422 mA h g-1 and 1232 mA h cm-3, respectively, at 100 mA g-1 with ∼97.5% capacity retention after 300 cycles. The excellent high-rate capability of 318 mA h g-1 at 6400 mA g-1 corroborates the stru...
Source: Nano Energy - Category: Nanotechnology Source Type: research