Flexible construction of three-dimensional continuous conductive structure by hollow carbon sphere and CNT for promoted ions transport in flow-electrode capacitive deionization

•The 3D continuous conductive network HCS@CNT is flexibly constructed as flow-electrode.•HCS@CNT flow-electrode exhibits excellent rheological behavior with good hydrophilicity.•HCS@CNT flow-electrode presents high average salt removal rate and prominent charge efficiency.•HCS@CNT demonstrates large potential for treating high concentration of salt solution.•DFT calculation reveals HCS@CNT is conducive to the interfacial charge transfer from HCS to CNT.