α‐MnO<sub>2</sub> Nanowires: A Catalyst for the O<sub>2</sub> Electrode in Rechargeable Lithium Batteries

Débart, Aurélie; Paterson, Allan J.; Bao, Jianli; Bruce, Peter G.

doi:10.1002/anie.200705648

Cited by 895 publications

(821 citation statements)

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“…The Bruce group have investigated the effect of various catalysts on electrochemical performance. [ 41 ] [ 42 ] Among them, α -MnO 2 nanowires showed the best electrochemical performance, delivering about 3000 mAhg − 1 at a current density of 75 mAg − 1 , and showing a stable cycle performance for 10 cycles ( Figure 4 ). This group suggested that the improvement is due to the crystal structure having 2 × 2 tunnels formed by edge-and corner-sharing MnO 6 octahedra.…”

Section: Catalystmentioning

confidence: 99%

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

Lee

Kim

Cao

et al. 2010

Advanced Energy Materials

2,054

1,216

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In the past decade, there have been exciting developments in the fi eld of lithium ion batteries as energy storage devices, resulting in the application of lithium ion batteries in areas ranging from small portable electric devices to large power systems such as hybrid electric vehicles. However, the maximum energy density of current lithium ion batteries having topatactic chemistry is not suffi cient to meet the demands of new markets in such areas as electric vehicles. Therefore, new electrochemical systems with higher energy densities are being sought, and metal-air batteries with conversion chemistry are considered a promising candidate. More recently, promising electrochemical performance has driven much research interest in Li-air and Zn-air batteries. This review provides an overview of the fundamentals and recent progress in the area of Li-air and Zn-air batteries, with the aim of providing a better understanding of the new electrochemical systems.

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Section: Catalystmentioning

confidence: 99%

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

Lee

Kim

Cao

et al. 2010

Advanced Energy Materials

2,054

1,216

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“…27,28 Rutile MnO 2 , particularly in nanowire form, has been demonstrated to reduce overpotentials and improve the cycling stability of the Lioxygen system. 8,29 Recent studies, however, have emphasized the presence of electrolyte decomposition in these earlier works, making the efficacy of catalysts less clear. 30−33 Nevertheless, with more recent demonstrations of the Li−O 2 system being cycled with good electrolyte stability 34,35 it is likely that the role of catalysts will become a focus of future studies.…”

Section: ■ Introductionmentioning

confidence: 99%

Rutile (β-)MnO₂ Surfaces and Vacancy Formation for High Electrochemical and Catalytic Performance

2014

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MnO 2 is a technologically important material for energy storage and catalysis. Recent investigations have demonstrated the success of nanostructuring for improving the performance of rutile MnO 2 in Li-ion batteries and supercapacitors and as a catalyst. Motivated by this we have investigated the stability and electronic structure of rutile (β-)MnO 2 surfaces using density functional theory. A Wulff construction from relaxed surface energies indicates a rod-like equilibrium morphology that is elongated along the c-axis, and is consistent with the large number of nanowire-type structures that are obtainable experimentally. The (110) surface dominates the crystallite surface area. Moreover, higher index surfaces than considered in previous work, for instance the (211) and (311) surfaces, are also expressed to cap the rod-like morphology. Broken coordinations at the surface result in enhanced magnetic moments at Mn sites that may play a role in catalytic activity. The calculated formation energies of oxygen vacancy defects and Mn reduction at key surfaces indicate facile formation at surfaces expressed in the equilibrium morphology. The formation energies are considerably lower than for comparable structures such as rutile TiO 2 and are likely to be important to the high catalytic activity of rutile MnO 2 . ■ INTRODUCTIONEnergy storage for hybrid electric vehicles and renewable energy sources is a pressing technological challenge for which Li-ion batteries and supercapacitors are key candidate systems. The conventional Li-ion intercalation cathode, LiCoO 2 , faces challenges of toxicity and high cost. Current supercapacitors based on carbon cathodes are limited by their storage capacity. The demand for higher capacity and higher power energy storage has led to a surge in interest in nanostructured electrodes. 1 Nanostructuring has been shown to improve the energy storage properties of rutile MnO 2 for both Li-ion batteries 2,3 and supercapacitors. 4−6 However, the mechanisms for this improvement are not fully understood on the atomic-scale. In addition to its role as an electrode material, nanostructured rutile MnO 2 has been shown to give good performance as a catalyst, 7 with much recent interest in its potential role in the Li−O 2 battery. 8 Knowledge of the surface features of rutile MnO 2 at the atomic and electronic level would provide valuable information regarding its energy storage and catalytic mechanisms. With the clear impetus to better understand the performance of rutile MnO 2 in three technologies, Li-ion batteries, supercapacitors and catalysis, in this work we apply first-principles simulations to understand surface phenomena in this promising material.Rutile MnO 2 is the subject of extensive research for its applications in Li-ion batteries, but early work indicated that bulk samples did not allow significant Li-ion intercalation. 2,9,10

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“…Although the specific chemistry of the physical structure residing at the cathode (the "air electrode") can be varied, it must be structurally sound, conductive, and effectively catalyze the oxygen reduction reaction. Typically, a composite comprising a conductive material physically mixed with an oxygen reduction catalyst is utilized, often integrated with binder 10,11 and a metal mesh as support. 32,33 Thus, the conventional approach to air electrodes positions catalyst particles randomly throughout the thickness of the composite electrode, analogous to the positioning of active material particles within a conventional battery electrode (Fig.…”

Section: Metal Air Cathodesmentioning

confidence: 99%

Secondary Battery Science: At the Confluence of Electrochemistry and Materials Engineering

2012

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Considerations of energy density, power, and calendar life are critical to effectively develop advanced secondary systems. For next generation battery applications requiring multiple features including long life, large cycle count, high energy density and high power, new strategies are needed for the rational design of electroactive materials and electrodes. This article discusses several conceptual approaches under exploration with examples from our research group. The first approach is the systematic synthesis of materials with structures facilitating ion insertion and deinsertion at high voltage and energy density, where we control materials properties such as surface area, particle size and in particular crystallite size. A second approach is the investigation of novel electrode structures and substrates to increase energy density and capacity retention under cycling, where we have developed strategies for minimizing passive components. A third approach is investigation of catalysts for metal air batteries where the cathode active material is drawn from the air rather than carried in the battery.

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α‐MnO₂ Nanowires: A Catalyst for the O₂ Electrode in Rechargeable Lithium Batteries

Cited by 895 publications

References 12 publications

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

Rutile (β-)MnO₂ Surfaces and Vacancy Formation for High Electrochemical and Catalytic Performance

Secondary Battery Science: At the Confluence of Electrochemistry and Materials Engineering

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α‐MnO2 Nanowires: A Catalyst for the O2 Electrode in Rechargeable Lithium Batteries

Cited by 895 publications

References 12 publications

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

Metal–Air Batteries with High Energy Density: Li–Air versus Zn–Air

Rutile (β-)MnO2 Surfaces and Vacancy Formation for High Electrochemical and Catalytic Performance

Secondary Battery Science: At the Confluence of Electrochemistry and Materials Engineering

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Product

Resources

About

α‐MnO₂ Nanowires: A Catalyst for the O₂ Electrode in Rechargeable Lithium Batteries

Rutile (β-)MnO₂ Surfaces and Vacancy Formation for High Electrochemical and Catalytic Performance