Enhanced manganese dioxide supercapacitor electrodes produced by electrodeposition

Fast Ionic Diffusion-Enabled Nanoflake Electrode by Spontaneous Electrochemical Pre-Intercalation for High-Performance Supercapacitor

“…Consequently, higher sodium content is obtained in the final electrodeposited product of Na x MnO 2 ( x = 0.91), confirmed by XRD results. The finding of hybrid MnO 2 phase in the final product is consistent with previous reports of electrodeposition1017192021394041, which indicates simultaneous formation of MnO 2 with spontaneous intercalation of Na + ions in MnO 2 interlayers. The XRD results further confirm that the intercalation of Na + ions into MnO 2 interlayers is time dependent with phase transition from Na 0.7 MnO 2 to Na 0.91 MnO 2 .…”

“…Currently, solutions for electrodeposited MnO 2 were reported to be consisted of Mn (II) compounds such as MnSO 4 or Mn(CH 3 COO) 2 as manganese sources17192021394041, and 0.1–0.2 M Na 2 SO 4 as additives172041. In our work, 0.02 M Mn(CH 3 COO) 2 and 1 M Na 2 SO 4 were used as mother solution, which provided a much larger concentration ratio (Na + :Mn 2+ = 100:1), so as to conduct the intercalation of Na + ions in MnO 2 layers by electrodeposition.…”

“…While for rate-controlling step (iii), it is important to improve the long-distance ionic diffusion ability from electrolyte to the solid phase, which is very difficult for traditional MnO 2 1213. To solve this problem, researchers reduce the diffusion resistance in the solid phase by decreasing the size and shortening the diffusion paths13141516, facilitated the ionic diffusion between MnO 2 and electrolyte by constructing an interconnected porous system10171819202122, or even loading very small quantity of active mass to achieve high capacitance. However, those strategies can improve the diffusion and intercalation/deintercalation only on the surface or the interface, the low ionic diffusion inside the solid phase is still unsolved fundamentally.…”

Hydrothermal-synthesized Co(OH)2 nanocone arrays for supercapacitor application

“…In the past decade, lots of research has been dedicated to investigating pseudocapacitive materials such as hydroxides [4,5], oxides [6,7], and polymers [8,9], which produce increased specific capacitances and high energy densities. In recent years, Cobalt species materials such as Co(OH) 2 , CoOOH, and Co 3 O 4 have attracted great attention due to their excellent electrochemical reversibility and cycle life and high capacitances [10e12].…”

Electrodeposition: a versatile, efficient, binder-free and room temperature one-step process to produce MnO2 electrochemical capacitor electrodes

“…in some cases higher than 2000 F g À1 , which strongly depends on the preparation method. 26 The SC value in MnO 2 lms has been depicted to decrease with increasing lm thickness, mostly owing to a combination of reduced electrolyte access and increased distance from the current collector, which lead to increased electrical resistance. 27 Additionally, the grain renement and more amorphous structure that occurs in the electrodeposited lms with increasing i c also contributes to the higher SC values achieved.…”