Interconnected core–shell MoO2 microcapsules with nanorod-assembled shells as high-performance lithium-ion battery anodes

Abstract

In this paper, a facile and template-free one-step strategy has been developed to synthesize interconnected core-shell MoO 2 hierarchical microcapsules via a solvothermal route. The assynthesized MoO 2 microcapsules exhibit a core-shell hierarchical architecture, which integrates four beneficial features: carbon-free, hollow cavity, porous shell, and interconnected wall. Due to their unique nanostructure, when evaluated for lithium-storage properties, they exhibit a high specific capacity of 749.3 mA h g À1 in the first discharge at a rate of 1 C and high reversible capacity of 623.8 mA h g À1 after 50 cycles. Meanwhile, higher rate (2 C and 5 C) measurements show that the carbon-free, core-shell MoO 2 microcapsules exhibit much better rate capacity even compared to MoO 2 -C nanocomposites tested under the same conditions. This superior electrochemical performance of the assynthesized microcapsules could be ascribed to, on the one hand, their inherently metallic electrical resistivity, and on the other hand, their special structure, which not only provides short Li ion pathways and high electronic and ionic conductivity, and but also be able to accommodate large volume variation.

Ultrathin MoO2 nanosheets for superior lithium storage

“…In the following cycles, the reversible capacity stabilizes at 1030 mAh g À 1 , while the CE drastically rises up to above 95%. Both the reversible capacity level and CE are significantly higher than reported values in literature, as most MoO 2 materials exhibited reversible capacities of 600-800 mAh g À 1 with initial CE below 70% [6,7,[9][10][11][12][13]18,20]. Although the pure MoO 2 prepared by reducing MoO 3 nanosheets with Ar/H 2 delivers a comparable discharge capacity, neither reversible capacity nor CE is comparable to the carbon coated nanosheets ( Figure S5).…”

“…As bulk MoO 2 generally shows poor Li storage capability due to kinetic barrier [4], diverse nanomaterials such as nanoparticles [5,6], nanowires [7,8], nanorods [9], nanobelts [10], and complex assemblies [11][12][13][14] have been engineered. These nanoscale materials exhibit upgraded Li-storage performance compared with bulk counterpart, due to higher surface areas, more active sites, and shorter ion diffusion paths [15][16][17].…”

Self-assembled porous MoO2/graphene microspheres towards high performance anodes for lithium ion batteries

“…The main driving force for the formation of unique 3D porous SA-MGH microsphere is due to: (i) Oriented attachment of particles to reduce the total surface energy leading to interconnected MoO 2 nanoparticles. In this process, adjacent nanoparticles are interconnected by sharing common crystallographic planes leaving voids in the structure [34].…”

Facile synthesis of monodisperse hierarchical MoO2 porous spheres for high-performance Li-ion battery

“…It is envisaged that the introduction of a hierarchical micro/nano-structure is an effective way to improve the electrochemical performance of MoO 2 materials [9,10]. However, there are far less reports on the hierarchical MoO 2 architectures compared with their low dimensional structures [11][12][13]. For example, hierarchical MoO 2 nanotube was obtained via template method in the present of CMK-3 [10].…”

“…Huang's group [11] reported a hierarchical MoO 2 nanoarchitecture through the calcination of Mo-containing precursors with hard templates in a H 2 atmosphere. Interconnected MoO 2 microcapsules have been prepared in acetophenone solvents [12]. Our group has synthesized yolk-shell MoO 2 via solvothermal method using isopropanol as solvents [13].…”