Space stability by incorporating iron atoms into the cobalt structure enabling capacitive deionization stability possible

Exploring and designing high performance pseudocapacitance electrode materials is of great significance in enhancing the desalination performance of capacitive deionization (CDI). Transition metal cobalt is considered a prospective electrode material for CDI because of its abundance and high theoretical capacity, which can produce a higher salt removal capacity than pure capacitive materials in the CDI process. However, due to the collapse and loss of the active electrode crystal matrix, the cobalt electrode exhibits poor electrochemical performance. In this work, we used a second metal element, Fe, introduced by ion exchange pyrolysis to regulate the leaching effect and optimize the ion matching for cobalt to protect the electrode structure. In addition, the interconnected external carbon layers form a robust matrix for enhanced electrical conductivity with ion transport. Thanks to the synergistic effect of the cobalt-iron (Co3Fe7@C) electrode structure and surface engineering, the adsorption capacity reached 72.29 mg.g(- 1), achieving 110 % capacity retention in 100 cycles of chlorine removal. As a result, the carbon-coated cobalt-iron bimetallic electrode exhibits excellent dechlorination capabilities in ca-pacity, cycle life and rate capability. This study provides a promising avenue for the design of stable electrode materials for capacitive deionization electrodes.