Spatially-confined electrochemical reactions of MoO3 nanobelts for reversible high capacity: Critical roles of glucose

MoO3-based layered structural oxides have long been exploited as promising electrode materials for lithium-ion batteries (LIBs), due to their high energy density and high cyclability. However, the limited interlayer spacing and their low electronic conductivity lead to capacity loss and low rate performance. This raises the crucial question whether good electrical conductivity of MoO3 with expanded interlayer spacing could be obtained to satisfy the requirements of high specific capacity and long durability. To solve this problem, herein, we introduce glucose for the modification of MoO3 powders by low-temperature vacuum drying. It is found that MoO3 can be readily reduced, bonded and spontaneously intercalated by glucose (MoO3-x@G). More importantly, glucose functioned as a cage to hold the pulverized MoO3-x pieces, while the subsequent conversion reaction of between Li2O, Mo and LixMoO3 occurred in confined space, which maintained electrodes structural integrity. As a result, the synthesized MoO3-x@G exhibits superior specific capacity and rate capability compared to pure MoO3. Furthermore, we demonstrate that the exceptional performance of MoO3-x@ G could be ascribed to the capacitive contribution and high reversible reaction. Our results give a unique insight into understanding the detailed electrochemical conversion processes of conversion-type electrode materials for application in high-performance LIBs.