2D layered Sb2Se3-based amorphous composite for high-performance Li- and Na-ion battery anodes.

A two-dimensional layered Sb 2 Se 3 -based amorphous composite (a –Sb 2 Se 3 /C) is synthesized using a simple solid-state ball-milling process, and its potential for Li- and Na-ion batteries is evaluated. Ex situ extended X-ray absorption fine structure analyses clearly indicate the electrochemical reaction mechanisms of Sb 2 Se 3 and a –Sb 2 Se 3 /C as anodes for Li- and Na-ion batteries. During Li- and Na-insertion, the Sb 2 Se 3 and a –Sb 2 Se 3 /C electrodes are converted into the final phases of Li 3 Sb/Na 3 Sb and Li 2 Se/Na 2 Se, respectively. During Li- and Na-extraction, the Li 3 Sb/Na 3 Sb and Li 2 Se/Na 2 Se in the Sb 2 Se 3 electrode are converted into Sb and Se, showing a non-recovery reaction, whereas a recovery to the original Sb 2 Se 3 in the a –Sb 2 Se 3 /C electrode occurs after full Li and Na extraction. Owing to the interesting conversion/recovery reaction, the a –Sb 2 Se 3 /C electrode exhibits excellent electrochemical performance, such as high reversible capacities (Li-ion battery: 662 mAh g−1; Na-ion battery: 407 mAh g−1), a long cycle life with highly reversible capacities (Li-ion battery: 662 mAh g−1 and 1,205 mAh cm−3, respectively, after 100th cycle; Na-ion battery: 378 mAh g−1 and 688 mAh cm−3, respectively, after 50th cycle), and high rate capabilities (Li-ion battery: 623 mAh g−1 and 1,133 mAh cm−3 at 3C; Na-ion battery: 270 mAh g−1 and 492 mAh cm−3 at 2C). Image 1 • A layered Sb 2 Se 3 and its amorphous Sb 2 Se 3 /C composite is synthesized simply. • The reaction mechanisms during Li- and Na-insertion/extraction is demonstrated. • The Sb 2 Se 3 had conversion/non-recovery reactions during Li- and Na-reactions. • The Sb 2 Se 3 /C had conversion/full-recovery reactions during Li- and Na-reactions. • The amorphous Sb 2 Se 3 /C exhibited excellent electrochemical performances. [ABSTRACT FROM AUTHOR]