Manganese Dioxide (MnO2): A High-Performance Energy Material for Electrochemical Energy Storage Applications

Corpuz, Ryan D.; Juan‐Corpuz, Lyn Marie De; Kheawhom, Soorathep

doi:10.1007/978-3-030-53065-5_3

Cited by 2 publications

(2 citation statements)

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“…MXenes, the class of two-dimensional (2D) materials with chemical formula M n +1 X n T 2 (M is a transition metal, X is either carbon or nitrogen, T is a functional group like –O, –F, or −OH passivating the surface) discovered only about a decade ago, have grabbed the attention of the materials research community. This is due to the superior electrochemical performance of the first discovered MXene Ti 3 C 2 T x , over other established 2D materials like graphene, − transition metal dichalcogenides (VSe 2 , WS 2 ), and transition metal oxides (RuO 2 , , MnO 2 , − NiO). Flexibility in the composition makes MXenes suitable for the further exploration of enhanced functionalities by tweaking their compositions and structures.…”

Section: Introductionmentioning

confidence: 99%

Improved Charge Storage Capacity of Supercapacitor Electrodes by Engineering Surfaces: The Case of Janus MXenes

Das,

Ghosh

2024

J. Phys. Chem. C

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Surface engineering in two-dimensional (2D) materials has turned out to be a useful technique to improve their functional properties. By designing Janus compounds MM′C in the MXene family of compounds M 2 C, where the two surfaces are constituted by two different transition metals M and M′, we have explored their potentials as electrodes in a supercapacitor with an acidic electrolyte. Using density functional theory (DFT) in conjunction with the classical solvation model, we have made an indepth analysis of the electrochemical parameters of three Janus MXenes, passivated by oxygen: NbVC, MnVC, and CrMnC. Comparisons with the corresponding end-point MXenes Nb 2 C, V 2 C, Mn 2 C, and Cr 2 C are also made. We find that the surface redox activity enhances due to the formation of Janus, improving the charge storage capacities of MXene electrodes significantly. Our analysis reveals that the improved functionality has its root in the variations in the charge state of one of the constituents in the Janus compound, which, in turn, has its origin in the electronic structure changes due to surface manipulation. Our work, which is the first on the electrochemical properties of Janus MXenes for supercapacitor applications, suggests surface engineering by forming appropriate Janus compounds as a possible route to extract high energy density in MXene electrode−acidic electrolyte-based energy storage devices.

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Section: Introductionmentioning

confidence: 99%

Improved Charge Storage Capacity of Supercapacitor Electrodes by Engineering Surfaces: The Case of Janus MXenes

Das,

Ghosh

2024

J. Phys. Chem. C

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“…In the recent past, 3d transition metal (TM)-based electrocatalysts for HER have emerged due to their affordability and stability in an alkaline electrolyte. − Even though HER activity in an alkaline medium is more sluggish than that in an acidic medium, it offers a selection of a wide range of non-noble metals or metal oxides, produces hydrogen of better purity due to low gas diffusivity, and improves stability. , Out of several TM-based electrocatalysts, metal oxide nanosheets are getting the most attention recently due to their huge lateral size compared to thickness owing to unique electronic and physicochemical properties compared to their bulk material. − Being abundant, manganese oxides have tremendous applications as energy storage devices due to their low cost, high redox potential, and reasonably environment-friendly − nature. Layered δ-type MnO 2 (brinessite) produces a 2D MnO 2 NS upon exfoliation of the mother layered crystal.…”

Section: Introductionmentioning

confidence: 99%

Exfoliated Cobalt-Doped Manganese Oxide Nanosheets: An Efficient and Stable Electrocatalyst for Hydrogen Evolution Reaction in an Alkaline Medium

Patra,

Laha,

Ghosh

2024

ACS Appl. Energy Mater.

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Endeavors toward designing and developing an easy-to-use, durable, effective, and non-noble-metal-based electrocatalyst for hydrogen evolution reaction (HER) are still ongoing. Two-dimensional (2D) transition metal oxide nanosheets (NSs) are now at the forefront of the race due to their huge lateral size compared to thickness owing to unique electronic and physicochemical properties compared to their bulk material and edge atom sites offering catalytic centers for HER. In this report, Co-doped MnO 2 [Mn 1−x Co x O 2 , x = 0.0−0.5] NSs were synthesized through chemical exfoliation. The electrochemical performance of different degrees of Co-doped MnO 2 NS samples toward HER was assessed in 1 M KOH solution by drop casting the NS dispersion on Ti foil. The superiority toward HER of exfoliated samples of any degree of Co doping in MnO 2 (x = 0.0−0.5) NSs compared to their bulk samples was observed. Within exfoliated samples, 20% Co-doped MnO 2 showed relatively better performance compared to other compositions with an overpotential of 218 mV at a 10 mA cm −2 current density and a Tafel slope of 122 mV dec −1 . Not only does it offer a reasonably low overpotential for HER but also provides a stable current density of ∼10 mA cm −2 for ∼12 h at the given overpotential. The substantially enhanced performance by 20% Co-doped MnO 2 NSs can be attributed to larger oxygen vacancies, preferential adsorption of water molecules, higher electrical conductivity, and fast charge transfer rate. Interestingly, the electrode preparation using this Co-doped MnO 2 NS dispersion adopted here does not involve usage of either any binder or conductive carbon, and the overpotential observed is either quite low or comparable to the state-of-the-art catalysts known of similar type in an alkaline medium. This study offers a highly potential and cost-effective scalable two-dimensional non-noble-metal-based electrocatalyst for HER in practical application.

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Manganese Dioxide (MnO2): A High-Performance Energy Material for Electrochemical Energy Storage Applications

Cited by 2 publications

References 73 publications

Improved Charge Storage Capacity of Supercapacitor Electrodes by Engineering Surfaces: The Case of Janus MXenes

Improved Charge Storage Capacity of Supercapacitor Electrodes by Engineering Surfaces: The Case of Janus MXenes

Exfoliated Cobalt-Doped Manganese Oxide Nanosheets: An Efficient and Stable Electrocatalyst for Hydrogen Evolution Reaction in an Alkaline Medium

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