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The lack of freshwater is one of the most serious problems for human beings in the 21st century.In order to generate fresh water from sea water and brackish water, variousdesalination methods have been researched and widely applied for waterdesalination such as distillation, electrodialysis, reverse osmosis, activatedcarbon adsorption, ion exchange method, etc. Capacitive deionization (CDI)technology is becoming increasly attractive as an alternative desalinationmethod due to low energy consumption, highwater recovery rate, easy operation with no secondary pollution and therenewable characteristic of the electrode. [1-2] Theprinciple is illustrated in Scheme 1. The high capacitive and high conductive electrodematerials in CDI setup are needed in order to enhance the accumulation of ionsand decrease energy consumption. Electrospun technique is very suitable forcarbon nanofiber material fabrication with high specific surface area andconductivity. By adjusting the composition of the polymer solution, the fiberswith different structure and morphology can be obtained. In this paper, theself-sustainable meso/micro-porous carbon fibers were fabricated by mixingdifferent additives such as inorganic salts (ZnCl2, ZnAc) oramorphous polymers PMMA in the polyacrylonitrile solution as pore-formingcomponents, followed by carbonization. The pore size and density can be tunedby adjusting the ratio of the additives. Cyclic voltammetry experimentconfirmed that the specific capacitiance of the carbon fiber has a significantincrease compared with the pure PAN drived carbon fiber. The capacitivedesalination performance has a great improvement with the salt removal amount 5times higher than pure PAN based fiber. It demonstrates that the mesoporouscarbon fiber electrode based supercapacitor is potential for water softing andbrackish water desalination application.