Hollow Carbon Spheres with Mesoporous Shell Structure for High Li Storage Capacity and Better Cycling Performance

New energy technologies are critical for the energy future that seeks the goal of sustainable energy development. Rechargeable lithium ion batteries are becoming a key-enabling technology and have potential applications in electric and hybrid vehicles due to their high energy density, high voltage, and long lifespan. However, their rate capability which is dominated by the diffusion rate of lithium ions and the electron transport in electrode materials, needs to be improved greatly. Recently, much attention has been paid to high surface area porous carbons with various nanostructures due to the expected reduced diffusion length of lithium ions and rapid charge transfer.

Hollow core-mesoporous shell carbon (HCMSC) spheres with hierarchical nanostructure were prepared and explored as anode material in Li ion battery. Compared with commercial graphite and ordered mesoporous carbon (CMK-3), the HCMSC not only demonstrates higher Li storage capacity, but also better cycling performance and rate capability. The HCMSC possesses unique structural characteristics such as large surface area and mesopore volume, and particularly the multimodal porositiy composed of hollow macropore core and well-developed 3D interconnected mesopores embedded in the mesopore shells, facilitating fast mass transport and charge transfer. The enhancement in anode performance especially in the cycling performance and rate capability is mainly attributable to the superb structural characteristics of the HCMSC, particularly the macropore core encapulated in well-developed 3D interconnected mesoporous shell, which possibly act as efficient Li storage and buffer reservoirs to reduce volume change during the charge–discharge cycling especially at high rates.