Intrinsic voltage plateau of a Nb(2)CTx MXene cathode in an aqueous electrolyte induced by high-voltage scanning

XL Li and XY Ma and Y Hou and ZH Zhang and Y Lu and ZD Huang and GJ Liang and MA Li and Q Yang and JL Ma and N Li and BB Dong and Q Huang and FR Chen and J Fan and CY Zhi, JOULE, 5, 2993-3005 (2021).

DOI: 10.1016/j.joule.2021.09.006

Although MXene has been widely used in many energy storage systems, the absence of a high intrinsic voltage plateau results in its poor discharging feature. Herein, we report a Nb(2)CTx MXene cathode with an apparent discharge voltage plateau for high-performance aqueous zinc ion batteries. Triggered by a repeated high voltage scanning up to 2.4 V, the Nb(2)CTx cathode gradually displays a stable Zn2+ storage dominated by a battery behavior. A high discharge voltage plateau of 1.55 V is presented, which is distinct from all reported MXene electrodes. Consequently, a record-level energy density among all aqueous MXenes electrodes of 146.7 Wh kg(-1) with a 63% contribution from the plateau region is obtained, which is 292% that of the capacitive Nb(2)CTx electrode. The developed high-voltage scanning strategy is also effective for Ti(3)C(2)Tx MXene to achieve a remarkable voltage plateau.

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