Study on the effect of oxidation on the cycling stability of MXene for capacitive deionization

MXene Ti 3 C 2 T x and Ti 2 CT x were introduced as CDI electrodes to investigate the effect of oxidation on desalination performance. In NaCl solution, Ti 3 C 2 T x maintained 65.6% of initial desalination capacity (14.05 mg/g) after 38 cycles and Ti 2 CT x maintained 23.5% after 12 cycles (10.14 mg/g). However, in deoxygenated NaCl solution, Ti 3 C 2 T x still maintained 87.8% after 134 cycles while Ti 2 CT x maintained 17.9% after 16 cycles. Subsequent analysis indicated that MXene was partially oxidized to TiO 2 , resulting in an increase of electrical resistance, which ultimately reduced cycling stability. This work implied that deoxygenating seawater is a significant method for the industrial application of Ti 3 C 2 T x .