Filling few-layer ReS2 in hollow mesoporous carbon spheres for boosted lithium/sodium storage properties

A facile and feasible spatial confinement strategy is proposed for the preparation of ultrathin ReS2 nanosheets confined in hollow mesoporous carbon spheres (HMCSs), forming nanosheets filled hollow carbon spheres (NSFHCSs) ReS2@C. Based on the spatially confined growth, the as-synthesized ReS2@C nanocomposites achieve novel filled-structure and well-defined heterogeneous interfaces. In the excellent architecture, the porous carbon framework precisely constrains ultrathin ReS2 nanosheets within its void space, which can generate essential electrical contacts, buffer volume expansion, and prohibit the loss of active materials during the pulverization process. For lithium-ion batteries, the NSFHCSs ReS2@C display high adsorption energy of Li in the heterogenous interface by the first-principle calculation, and achieve superior reversible capacity of 578 ​mA ​h ​g−1 after 1000 cycles at 1 ​A ​g−1. Research shows that the capacitive behavior plays a major role in specific capacity contribution of ReS2@C electrode. For sodium-ion batteries, the NSFHCSs ReS2@C demonstrate reversible discharge capacity of 319 ​mA ​h ​g−1 at 0.2 ​A ​g−1 after 400 cycles. The enlarged interlayer spacing and few layer structure of ReS2 nanosheets are conducive to enhance the Li+/Na+ mobility and improve the dynamic characteristic of electrode material.