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Mn-based oxides are efficient pseudocapacitive electrode materials and have been investigated for capacitive deionization (CDI). However, their poor conductivity seriously affects their desalination performance. In this work, polyaniline coated Mn 2 O 3 nanorods (PANI/Mn 2 O 3 ) are synthesized by oxidizing a Mn-based metal organic framework (MOF) and subsequent in-situ chemical polymerization. The polyaniline not only acts as a conductive network for faradaic reactions of Mn 2 O 3 , but also enhances the desalination rate. PANI/Mn 2 O 3 has a specific capacitance of 87 F g -1 (at 1 A g -1 ), superior to that of Mn 2 O 3 nanorod (52 F g -1 at 1 A g -1 ). The hybrid CDI cell constructed with a PANI/Mn 2 O 3 cathode and an active carbon anode shows a high desalination capacity of 21.6 mg g -1 , superior recyclability with only 11.3% desalination capacity decay after 30 desalination cycles and fast desalination rate of 2.2 mg g -1 min -1 . PANI/Mn 2 O 3 is a potential candidate for high performance CDI applications., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The design of high-performance electrode materials with excellent desalination ability has always been a research goal for efficient capacitive deionization (CDI). Herein, a hybrid architecture with Cu/Cu 2 O nanospheres anchored on porous carbon nanosheets (Cu/Cu 2 O/C) was first synthesized by pyrolyzing a two-dimensional (2D) Cu-based metal-organic framework and then evaluated as a cathode for hybrid CDI. The as-prepared Cu/Cu 2 O/C exhibits a hierarchically porous structure with a high specific surface area of 305 m 2  g -1 and large pore volume of 0.55 cm 3  g -1 , which is favorable to accelerating ion migration and diffusion. The porous carbon nanosheet matrix with enhanced conductivity will facilitate the Faradaic reactions of Cu/Cu 2 O nanospheres during the desalination process. The Cu/Cu 2 O/C hybrid architecture displays a high specific capacitance of 142.5 F g -1 at a scan rate of 2 mV s -1 in 1 M NaCl solution. The hybrid CDI constructed using the Cu/Cu 2 O/C cathode and a commercial activated carbon anode exhibits a high desalination capacity of 16.4 mg g -1 at an operation voltage of 1.2 V in 500 mg L -1 NaCl solution. Additionally, the hybrid CDI exhibits a good cycling stability with 18.3% decay in the desalination capacity after 20 electrosorption-desorption cycles. Thus, the Cu/Cu 2 O/C composite is expected to be a promising cathode material for hybrid CDI., (Copyright © 2022 Elsevier Inc. All rights reserved.)