Cage-like MnSe@PPyC/rGO as superior dual anode materials in Li/Na-ions storage

Abstract

Along with high reversible capacity, superior cycling and rate performances, transition metal-based materials have been considered as promising dual anode materials for lithium/sodium ion storage. However, one of the greatest challenges during the selenization process is that the as-prepared transition metal selenides with designed morphology could retain the original morphology of transition metal oxides well. To address this key issue, in this work, a cage-like MnSe@PPyC/rGO composite is successfully developed by one-step selenization/carbonization treatment with in-situ formed polypyrrole coated MnO2 nanorods and graphene oxide as precursors, which effectively preserve the original rod-like morphology and endow a conductive network. The morphology control process, composition and microstructural change have been systematically characterized with SEM, EDS, TEM, TGA, BET, XRD, and XPS. Benefited from the above composition and structure, cage-like MnSe@PPyC/rGO exhibits good rate performance (310.3 mAh/g at 3.2 A/g) and high reversible lithium storage capacity (776.9 mAh/g at 0.1 A/g after rate testing). As anode materials for SIBs, the composite demonstrates high capacity of 546.6 mAh/g at 0.2 A/g as well as outstanding rate capability and cycle stability (294.4 mAh/g after 455 cycles at 2 A/g and 194.5 mAh/g after 2000 cycles at 10 A/g). The finding provides a new avenue for the study of transition metal/carbon composites with special morphology as dual anode materials for Li/Na-ions storage.