Hollow mesoporous carbon nanospheres space-confining ultrathin nanosheets superstructures for efficient capacitive deionization.

In this work, we propose a novel strategy to fabricate nickel silicate nanoflakes inside hollow mesoporous carbon spheres (NiSiO(OH)/C). Hollow mesoporous carbon spheres (HMCSs) can well regulate and limit the growth of NiSiO(OH) nanosheets, which obviously enhance the structural stability and conductivity of the composites. The core-shell NiSiO(OH)/C superstructure has been proven to possess an extremely excellent electrosorption capacity of 28.7 mg g at 1.2 V under a NaCl concentration of 584 mg L for capacitive deionization (CDI). This outstanding property can be attributed to the core-shell superstructure with ultrathin NiSiO(OH) nanosheets as the stable core and mesoporous carbon as the conductive shell. This work will provide a direction for the application of core-shell superstructure carbon-based nanomaterials as high-performance electrode materials for CDI.