In order to enhance the desalting performance of electrode in the capacitive deionization process (CDI), a novel sulfobutyl ether beta-cyclodextrin polymer with multi-sulfonic groups and multi-hydroxyl groups (SBE-beta-CDP) was successfully synthesized and attached on the surface of carbon nanotubes (CNT) by non-covalent bond. The as-prepared CNT@SBE-beta-CDP electrode possesses significantly improved capacitance property and hydrophilicity (60.9 F/g, 65.5 degrees) as compared to the CNT electrode (51.7 F/g, 103.6 degrees), which indicates that the multi-sulfonic groups and multi-hydroxyl groups on the CNT@SBE-beta-CDP electrode surface can provide efficient ion transfer pathway by the synergistic effect. The symmetric and asymmetric CDI cells, named as R parallel to R, R(+)parallel to R-CDP(-) and R-CDP(+)parallel to R(-), were assembled with the CNT electrode (R) and CNT@SBE-beta-CDP electrode (R-CDP). Based on the electroneutrality principle of electrode, the theoretical analysis about the adsorption process of these CDI cells by balancing the ionic charge, electronic charge and chemical charge in the electrode demonstrates that when the CNT@SBE-beta-CDP electrode is used as cathode, the theoretical charge efficiency reaches a maximum in the asymmetric R(+)parallel to R-CDP(-). In the desalting experiments, the average salt adsorption capacity and charge efficiency for R(+)parallel to R-CDP(-) (6.37 mg/g, 36.9%) surpass those of R parallel to R (4.17 mg/g, 25.8%) and R-CDP(+)parallel to R(-)(3.11 mg/g, 17.3%). These facts confirm the good cation selectivity of CNT@SBE-beta-CDP electrode that strengthens the desalting performance of asymmetric CDI process. (C) 2019 Elsevier Ltd. All rights reserved.