Facile fabrication of intercalation-type pseudocapacitive S-Ti3C2Tx/PANI/F-Ti3C2Tx cathode for asymmetric capacitive deionization.

Although tremendous efforts have been paid on Ti 3 C 2 T x as a cathode for capacitive deionization (CDI), its structural instability and easy agglomeration have always limited such a promising application. In this study, a hybrid of hollow Ti 3 C 2 T x spheres and flakes was synchronously fabricated by a novel sacrificial-templated method for the first time, and then immobilized/bonded together by in-situ polymerization of polyaniline, which was labelled as S-Ti 3 C 2 T x /PANI/F-Ti 3 C 2 T x. The highest specific capacitance of S-Ti 3 C 2 T x /PANI/F-Ti 3 C 2 T x in 1 M NaCl solution was measured to be 102 F·g−1, and diffusion capacitance of the as-obtained S-Ti 3 C 2 T x /PANI/F-Ti 3 C 2 T x was calculated to be 63%. Thus, a high salt adsorption capacity of 76 mg·g−1 with a maximum salt adsorption rate of 11.45 mg·g−1·min−1 was obtained, which is much higher than that of Ti 3 C 2 T x -related materials in literature for asymmetric CDI system. Moreover, such a superior desalination performance was verified stable at almost 100% after 30 cycles. Besides the ion intercalation and fluoro/hydroxyl groups of Ti 3 C 2 T x , the high performance and stability of the as-obtained S-Ti 3 C 2 T x /PANI/F-Ti 3 C 2 T x should also be ascribed to the beneficial effects of immobilization/bonding role of conductive PANI between S-Ti 3 C 2 T x and F-Ti 3 C 2 T x. This study gives a new perspective to promote the real applications of CDI by designing highly capacitive and stable electrode materials. [Display omitted] • A kind of S-Ti 3 C 2 T x /PANI/F-Ti 3 C 2 T x as intercalation-type pseudo-capacitive cathode electrode was invented. • The S-Ti 3 C 2 T x /PANI/F-Ti 3 C 2 T x electrode has high salt adsorption capacity with 76 mg g-1. • The salt adsorption capacity of S-Ti 3 C 2 T x /PANI/F-Ti 3 C 2 T x electrode remained at almost 100% after 30 cycles. [ABSTRACT FROM AUTHOR]