Electrodeposited Manganese Dioxide/Activated Carbon Composite As a High-Performance Electrode Material for Capacitive Deionization

Abstract

Electrode materials are a crucial component for achieving high desalination performance via capacitive deionization (CDI). In the present work, we have successfully fabricated a manganese dioxide (MnO2)/activated carbon (AC) composite electrode using an anodic electrodeposition technique. Surface characterization confirms the presence of electrodeposited MnO2 on the AC surface with an amorphous structure and improved wetting behavior. Cyclic voltammetry and galvanostatic charge/discharge measurements indicate that the MnO2/AC composite electrode exhibits a high specific capacitance (77.6 F g–1 at 5 mV s–1), rate capability, and excellent cycling reversibility for capacitive charge storage. Furthermore, the salt electrosorption capacity is investigated using batch mode experiments at a working voltage of 1.0 V in a 0.01 M NaCl solution. The MnO2/AC composite electrode presents a superior electrosorption capacity of 9.3 mg g–1, which is approximately 1.6-fold higher than that of the pure AC electrode (5.7 mg g–1). This significant improvement can be attributed to the mixed capacitive-Faradaic process, corresponding to the combination of the double-layer charging of the high specific surface area (625 m2 g–1) and the pseudocapacitive redox reaction of MnO2. Therefore, the electrodeposited MnO2/AC composite is a potential electrode material for high-performance CDI.

Controllable Carbonization of Plastic Waste into Three-Dimensional Porous Carbon Nanosheets by Combined Catalyst for High Performance Capacitor

“…The weight loss in the range of 300~450 °C is due to the oxidation of PCS. In addition, due to chemical reaction of MnO 2 to Mn 2 O 3 , a weak weight loss is also found after 450 °C [ 36 ]. Figure 3 b presents the Raman spectra of CP, PCS and PCS-MnO 2 -2, respectively.…”

Faradaic Electrodes Open a New Era for Capacitive Deionization

“…Apart from manganese oxides with unique crystalline structures, various amorphous manganese oxides have been applied as Faradaic electrodes for CDI as well. [ 76,108,159–162 ] For instance, Wu et al. [ 76 ] employed an amorphous MnO 2 as a Faradaic electrode for a HCDI cell, which exhibited an ion removal capacity of 14.9 mg g −1 in 500 mg L −1 NaCl solution and maintained 95.4% of the initial capacity after 350 cycles.…”

“…Moreover, considering that the electronic conductivity of carbon materials (about 50 S cm −1 ) [ 163 ] is much higher than that of manganese oxides (10 −7 –10 −3 S cm −1 ), [ 164,152 ] carbon materials have been incorporated into manganese oxides to further improve their Faradaic charge‐transfer. [ 108,159,160,162 ] For example, Liu et al. successively developed a manganese dioxide/activated carbon (MnO 2 /AC) composite [ 159 ] and manganese dioxide/carbon nanotube‐chitosan composite (MnO 2 /CNT‐CS) [ 160 ] as Na + insertion Faradaic electrodes for CDI.…”

Preparation of Manganese Lignosulfonate and Its Application as the Precursor of Nanostructured MnOx for Oxidative Electrocatalysis

“…The former has been reported to undergo irreversible oxidation to a quinone-containing polymer, which, in turn, undergoes reversible proton-coupled two electron oxidation/reduction [4]. On the other hand, Mn 2+ ions have been reported to undergo the oxidation to manganese oxide(s) [20,21]. Figure 2A shows the cyclic voltammogram of Mn-LS in mixture with sodium sulfate as the supporting electrolyte.…”