Ordered hierarchical mesoporous/macroporous carbon: a high-performance catalyst for rechargeable Li-O(2) batteries.
TL;DR: Three-dimensional ordered mesoporous/macroporous carbon sphere arrays are synthesized and then used as a catalyst for Li-O2 batteries and the hierarchical porous structure of the MMCSAs facilitates electrolyte immersion and Li(+) diffusion and provides an effective space for O2 diffusion and O2 /Li2 O2 conversion.
Abstract: Three-dimensional ordered mesoporous/macroporous carbon sphere arrays (MMCSAs) are synthesized and then used as a catalyst for Li-O2 batteries. The hierarchical porous structure of the MMCSAs not only facilitates electrolyte immersion and Li(+) diffusion but also provides an effective space for O2 diffusion and O2 /Li2 O2 conversion, and thus efficiently improves the performance of Li-O2 batteries.
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TL;DR: A review of mesoporous materials can be found in this paper, where the authors summarize the primary methods for preparing mesopore materials and discuss their applications as electrodes and/or catalysts in solar cells, solar fuel production, rechargeable batteries, supercapacitors and fuel cells.
Abstract: To meet the growing energy demands in a low-carbon economy, the development of new materials that improve the efficiency of energy conversion and storage systems is essential. Mesoporous materials offer opportunities in energy conversion and storage applications owing to their extraordinarily high surface areas and large pore volumes. These properties may improve the performance of materials in terms of energy and power density, lifetime and stability. In this Review, we summarize the primary methods for preparing mesoporous materials and discuss their applications as electrodes and/or catalysts in solar cells, solar fuel production, rechargeable batteries, supercapacitors and fuel cells. Finally, we outline the research and development challenges of mesoporous materials that need to be overcome to increase their contribution in renewable energy applications. Mesoporous materials are finding increasing uses in energy conversion and storage devices. This Review highlights recent developments in the synthesis of mesoporous materials and their applications as electrodes and/or catalysts in solar cells, solar fuel production, rechargeable batteries, supercapacitors and fuel cells.
949 citations
TL;DR: The unified mechanism shows that low-donor-number solvents are likely to lead to premature cell death, and that the future direction of research for lithium-oxygen batteries should focus on the search for new, stable, high-donour-number electrolytes, because they can support higher capacities and can better sustain discharge.
Abstract: The mechanism of O2 reduction in aprotic solvents is important for the operation of Li–O2 batteries but is not well understood. A single unified mechanism is now described that regards previous models as limiting cases. It shows that the solubility of the intermediate LiO2 is a critical factor that dictates the mechanism, emphasizing the importance of the solvent.
881 citations
TL;DR: This work presents a novel and scalable approach to solve the challenge of integrating nanofiltration and X-ray diffraction for high-performance liquid chromatography of Na6(CO3SO4)(SO4)+.
Abstract: Liqiang Mai,*,† Xiaocong Tian,† Xu Xu,† Liang Chang,‡ and Lin Xu†,§ †State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, WUT-Harvard Joint Nano Key Laboratory, Wuhan University of Technology, Wuhan 430070, China ‡Department of Materials Science and Engineering, Michigan Technological University, Houghton, Michigan 49931-1295, United States Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
603 citations
TL;DR: A critical evaluation of the progress achieved so far is made, together with an attempt to propose future R&D trends, and a forecast on whether Li/air may have a role in the next years' battery technology is also postulated.
Abstract: Lithium/air is a fascinating energy storage system. The effective exploitation of air as a battery electrode has been the long-time dream of the battery community. Air is, in principle, a no-cost material characterized by a very high specific capacity value. In the particular case of the lithium/air system, energy levels approaching that of gasoline have been postulated. It is then not surprising that, in the course of the last decade, great attention has been devoted to this battery by various top academic and industrial laboratories worldwide. This intense investigation, however, has soon highlighted a series of issues that prevent a rapid development of the Li/air electrochemical system. Although several breakthroughs have been achieved recently, the question on whether this battery will have an effective economic and societal impact remains. In this review, a critical evaluation of the progress achieved so far is made, together with an attempt to propose future R&D trends. A forecast on whether Li/air may have a role in the next years' battery technology is also postulated.
521 citations
TL;DR: A novel Li-O2 battery with high reversibility and good energy efficiency using a soluble catalyst combined with a hierarchical nanoporous air electrode is reported, enabling ultra-efficient electrode reactions and significantly enhanced catalytic activity.
Abstract: The lithium–oxygen battery has the potential to deliver extremely high energy densities; however, the practical use of Li-O2 batteries has been restricted because of their poor cyclability and low energy efficiency. In this work, we report a novel Li-O2 battery with high reversibility and good energy efficiency using a soluble catalyst combined with a hierarchical nanoporous air electrode. Through the porous three-dimensional network of the air electrode, not only lithium ions and oxygen but also soluble catalysts can be rapidly transported, enabling ultra-efficient electrode reactions and significantly enhanced catalytic activity. The novel Li-O2 battery, combining an ideal air electrode and a soluble catalyst, can deliver a high reversible capacity (1000 mAh g−1) up to 900 cycles with reduced polarization (about 0.25 V).
435 citations
References
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TL;DR: The energy that can be stored in Li-air and Li-S cells is compared with Li-ion; the operation of the cells is discussed, as are the significant hurdles that will have to be overcome if such batteries are to succeed.
Abstract: Li-ion batteries have transformed portable electronics and will play a key role in the electrification of transport. However, the highest energy storage possible for Li-ion batteries is insufficient for the long-term needs of society, for example, extended-range electric vehicles. To go beyond the horizon of Li-ion batteries is a formidable challenge; there are few options. Here we consider two: Li-air (O(2)) and Li-S. The energy that can be stored in Li-air (based on aqueous or non-aqueous electrolytes) and Li-S cells is compared with Li-ion; the operation of the cells is discussed, as are the significant hurdles that will have to be overcome if such batteries are to succeed. Fundamental scientific advances in understanding the reactions occurring in the cells as well as new materials are key to overcoming these obstacles. The potential benefits of Li-air and Li-S justify the continued research effort that will be needed.
7,895 citations
TL;DR: In order to further improve the power and energy densities of the capacitors, carbon-based composites combining electrical double layer capacitors (EDLC)-capacitance and pseudo-Capacitance have been explored and show not only enhanced capacitance, but as well good cyclability.
Abstract: Carbon materials have attracted intense interests as electrode materials for electrochemical capacitors, because of their high surface area, electrical conductivity, chemical stability and low cost. Activated carbons produced by different activation processes from various precursors are the most widely used electrodes. Recently, with the rapid growth of nanotechnology, nanostructured electrode materials, such as carbon nanotubes and template-synthesized porous carbons have been developed. Their unique electrical properties and well controlled pore sizes and structures facilitate fast ion and electron transportation. In order to further improve the power and energy densities of the capacitors, carbon-based composites combining electrical double layer capacitors (EDLC)-capacitance and pseudo-capacitance have been explored. They show not only enhanced capacitance, but as well good cyclability. In this review, recent progresses on carbon-based electrode materials are summarized, including activated carbons, carbon nanotubes, and template-synthesized porous carbons, in particular mesoporous carbons. Their advantages and disadvantages as electrochemical capacitors are discussed. At the end of this review, the future trends of electrochemical capacitors with high energy and power are proposed.
2,497 citations
TL;DR: Operation of the rechargeable Li-O2 battery depends critically on repeated and highly reversible formation/decomposition of lithium peroxide (Li2O2) at the cathode upon cycling, and it is shown that this process is possible with the use of a dimethyl sulfoxide electrolyte and a porous gold electrode.
Abstract: The rechargeable nonaqueous lithium-air (Li-O(2)) battery is receiving a great deal of interest because, theoretically, its specific energy far exceeds the best that can be achieved with lithium-ion cells. Operation of the rechargeable Li-O(2) battery depends critically on repeated and highly reversible formation/decomposition of lithium peroxide (Li(2)O(2)) at the cathode upon cycling. Here, we show that this process is possible with the use of a dimethyl sulfoxide electrolyte and a porous gold electrode (95% capacity retention from cycles 1 to 100), whereas previously only partial Li(2)O(2) formation/decomposition and limited cycling could occur. Furthermore, we present data indicating that the kinetics of Li(2)O(2) oxidation on charge is approximately 10 times faster than on carbon electrodes.
1,712 citations
TL;DR: Chainmail for catalysts: a catalyst with iron nanoparticles confined inside pea-pod-like carbon nanotubes exhibits a high activity and remarkable stability as a cathode catalyst in polymer electrolyte membrane fuel cells (PEMFC), even in presence of SO(2).
Abstract: Chainmail for catalysts: a catalyst with iron nanoparticles confined inside pea-pod-like carbon nanotubes exhibits a high activity and remarkable stability as a cathode catalyst in polymer electrolyte membrane fuel cells (PEMFC), even in presence of SO(2). The approach offers a new route to electro- and heterogeneous catalysts for harsh conditions.
1,147 citations
TL;DR: PtAu nanoparticles were shown to strongly enhance the kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in rechargeable Li-O(2) cells, found to exhibit the highest round-trip efficiency reported to date.
Abstract: PtAu nanoparticles (NPs) were shown to strongly enhance the kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in rechargeable Li−O2 cells. Li−O2 cells with PtAu/C were found to exhibit the highest round-trip efficiency reported to date. During ORR via xLi+ + O2 + xe− → LixO2, the discharge voltage with PtAu/C was considerably higher than that of pure carbon and comparable to that of Au/C. During OER via LixO2 → xLi+ + O2 + xe−, the charge voltages with PtAu/C fell in the range from 3.4 to 3.8 VLi, which is slightly lower than obtained with Pt. It is hypothesized that PtAu NPs exhibit bifunctional catalytic activity, having surface Au and Pt atoms primarily responsible for ORR and OER kinetics in Li−O2 cells, respectively.
1,134 citations