▎ 摘　　要

Capacitive deionization (CDI) is an alternative water purification technology offering a suitable way to obtain drinkable water. Electrode materials are quite crucial for the deionization efficiency. Here, for the first time, a straightforward and cost-effective approach is developed to prepare 3D intercalated graphene sheet-sphere nanocomposite architectures as high-performance CDI electrodes by using graphene oxide and [Ni-2(EDTA)] as precursors. 3D graphene nanospheres between graphene sheets inhibit the restacking of graphene layers. Significantly, the as-prepared 3D mesoporous graphene sheet-sphere nanocomposite architectures possess high specific surface area and suitable pore size distribution. By using 3D mesoporous graphene sheet-sphere nanocomposite architectures as an electrode, an ultrahigh electrosorptive capacity of 22.09 mg g(-1) is achieved in a 500 mg L-1 NaCl solution at 1.2 V, and the salt removal percentage of the obtained electrodes is around 90%. Furthermore, the electrodes present good deionization stability and regeneration performance. This work also offers a promising solution to develop highly effective electrode materials in the CDI process for brackish and sea water desalination.