CaMoO4 Persimmon/MCMB composites with highly exposed (103) active facets and enhanced properties for reversible lithium storage

Abstract

The rapid and controllable synthesis of materials with specific exposed planes is regarded as a novel strategy to design electrodes, which is beneficial to promote the lithium-ion battery properties and to push the exciting developments. Herein, we revealed that the (103) plane of CaMoO4, possessing the least energy from the systematically simulative results of the first-principle calculations, is the preferred orientation for lithium ions migration from the surface to the bulk cavity. Therefore, three-dimensional CaMoO4 persimmon/mesocarbon-microbead (MCMB) microcomposites with exposed (103) active planes were designed via a facile microwave irradiation strategy, which is in favor of highly reversible Li+ insertion/extraction. Meanwhile, the crystallographic variations and phase changes of the CaMoO4/MCMB composites were investigated by in-situ X-ray diffraction, cyclic voltammetry and theoretical calculations to probe the lithium storage mechanism during charge-discharge cycling. In particular, the CaMoO4 persimmon/MCMB anode with 20.16 wt% CaMoO4 loading (Sample 2) exhibits a high initial specific capacity of 991.3 mAh g−1, a reversible capacity of 543.5 mAh g−1 even after 80 cycles, and a low apparent activation energy of 39.68 kJ mol−1 originating from the enhanced dynamic property. Besides, the variations of electrode materials on morphology over cycles were observed by scanning electron microscopy and transmission electron microscopy characterizations. The results demonstrate that the micro/nanostructures with exposed planes in the as-prepared CaMoO4/MCMB composites, achieving a good microtopology stability via tearing down the cell after cycles, are promising candidates for high-performance LIBs.