LAUSR

Abstract The metal selenides/tellurides have attracted considerable concerns for high-capacity lithium ion batteries (LiBs) because of their high conductivity, low voltage polarization and high theoretical coulombic efficiency. However, poor cyclability is still a big challenge that impedes their practical applications. Herein, GeSe2/Carbon (GeSe2/C) composite was fabricated by solid-state reaction method and its lithium ion (Li+) storage performances were investigated using flexible polyacrylonitrile (PAN) gel polymer electrolyte as separator. Reversible capacity of the GeSe2/C|PAN|Li system was ~20% higher than that of the GeSe2/C|polypropylene (PP)|Li system. Upon NaCl-assisted ball milling process, SEM and TEM observations revealed that the size of GeSe2/C particles significantly decreased from 30 μm to 100–500 nm. The milled GeSe2/C displayed a high capacity of 623.6 mA h g−1 at 350th cycle, which was 90.7% of the 2nd discharge capacity value, and the reversible capacity showed a 1100% improvement by using PAN as separator compared to the conventional PP separator. This study might inspire manufacturing of high-performance LiBs for energy storage.