MnO2 Heterostructure on Carbon Nanotubes as Cathode Material for Aqueous Zinc-Ion Batteries

Abstract

<jats:p>Due to their cost effectiveness, high safety, and eco-friendliness, zinc-ion batteries (ZIBs) are receiving much attention nowadays. In the production of rechargeable ZIBs, the cathode plays an important role. Manganese oxide (MnO2) is considered the most promising and widely investigated intercalation cathode material. Nonetheless, MnO2 cathodes are subjected to challenging issues viz. limited capacity, low rate capability and poor cycling stability. It is seen that the MnO2 heterostructure can enable long-term cycling stability in different types of energy devices. Herein, a versatile chemical method for the preparation of MnO2 heterostructure on multi-walled carbon nanotubes (MNH-CNT) is reported. Besides, the synthesized MNH-CNT is composed of δ-MnO2 and γ-MnO2. A ZIB using the MNH-CNT cathode delivers a high initial discharge capacity of 236 mAh g−1 at 400 mA g−1, 108 mAh g−1 at 1600 mA g−1 and excellent cycling stability. A pseudocapacitive behavior investigation demonstrates fast zinc ion diffusion via a diffusion-controlled process with low capacitive contribution. Overall, the MNH-CNT cathode is seen to exhibit superior electrochemical performance. This work presents new opportunities for improving the discharge capacity and cycling stability of aqueous ZIBs.</jats:p>

A comparison study of MnO2 and Mn2O3 as zinc-ion battery cathodes: an experimental and computational investigation

“…[5][6][7][8][9][10][11][12][13][14] This is due to their high specic capacity, low cost, and environmental friendliness. 3 The studies available on manganese dioxide cathodes for ZIBs mainly focus on MnO 2 , [15][16][17][18] (ref. 9 and 20) or mixed-valence manganese dioxide containing multiple phases.…”

Polypyrrole nanoparticles embedded nitrogen-doped graphene composites as novel cathode for long life cycles and high-power zinc-ion hybrid supercapacitors

“…If the b value is close to 0.5, the charge/discharge process is mainly controlled by ionic diffusion, while a b value of 1 indicates that pseudocapacitive behavior dominates the charge/discharge process. 37 As shown in Fig. 9B , the specific current plot exhibits a linear increase with the scan rate.…”

“…Obviously, it can be seen that as the scan rate increases, the current response in the CV area along with the maximum currents of the reduction and oxidation peaks is efficiently increased. The logarithm relationship between the peak currents and the scan rate is calculated using a power law to exemplify the charge storage mechanism, as shown in eqn (3) and (4) : 37 i = aν b ln i = b ln ν + ln a where i and ν are the peak specific current and scan rate, respectively, and a and b are adjustable parameters. Principally, the b value is represented by the slope of the plot, corresponding to the electrochemical characteristics of materials.…”

“…This result indicates that the charge/discharge mechanism of N-rGO4/PPy1 is mainly controlled by pseudocapacitive behavior combined with ion diffusion kinetics. The contribution mechanism of the assembled CR2032 cell of Zn//N-rGO4/PPy1 can be calculated using eqn (5) : 37–39 i = k 1 ν + k 2 ν 1/2 …”

Enhanced Cycling Performance of Rechargeable Zinc–Air Flow Batteries Using Potassium Persulfate as Electrolyte Additive

“…Such issues are responsible for a decrease in efficiency and poor cycling performance. These drawbacks can be mitigated by improving the air cathode configuration [10][11][12], modifying the Zn anode structure [13][14][15] or using electrolyte additives [16][17][18].…”