Hollow selenium/ferromanganese selenide nanospheres decorated with 3D porous graphene aerogel for enhanced lithium storage performance

Abstract Transition metal selenides have been considered as prospective anode materials for advanced lithium‐ion batteries due to the features of high theoretical capacity, environmentally friendly and abundant resource reserves. Nevertheless, the long‐term cycling stability property is limited owing to electrode structure disruption caused by huge volume expansion during cycling and the poor rate capability results from their poor intrinsic conductivity. Herein, the hollow selenium/ferromanganese selenide nanospheres (Se/MnFe 2 Se 4 ) were synthesized via a SiO 2 ‐assisted template method, which was decorated with 3D porous graphene aerogel with satisfactory structure and mechanical properties, forming the Se/MnFe 2 Se 4 /rGO composites. The prepared composites offered multiple advantages for enhancing lithium storage. First, hollow nanospheres can reduce ion/electron diffusion pathways, widen the surface area, and alleviate partial volume expansion. Meanwhile, Se was introduced into the composites to improve their conductivity and provided extra capacity by participating in the charging/discharging process. Besides, 3D porous graphene aerogels (rGO) provided more active sites, which improved the conductivity, shortened the transport path of ions and electrons, and effectively alleviated the stress concentration due to volume changes. The Se/MnFe 2 Se 4 /rGO composites showed stable cycling performance of 961.3 mAh g −1 at 0.1 A g −1 after 200 cycles and 638.7 mAh g −1 at 1.0 A g −1 after 2500 cycles. This work provided a novel anode electrode with a satisfactory electrochemical performance improvement strategy, which would promote the development of high‐performance LIBs and other energy storage devices.