Reimagine fuel cells Lemmon, John P
Nature (London),
09/2015, Volume:
525, Issue:
7570
Journal Article
Peer reviewed
Investments in solar photovoltaics and wind turbines are soaring as costs fall and governments and companies seek to reduce greenhouse-gas emissions. But fluctuating power from the wind and sun ...threatens to destabilize electricity grids. As more intermittent sources are connected, the power surges and crashes. This increases variability in voltage, in power and in the frequency of alternating current.
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DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
The increasing penetration of renewable energy and the trend toward clean, efficient transportation have spurred growing interests in sodium-beta alumina batteries that store electrical energy via ...sodium ion transport across a β″-Al
2O
3 solid electrolyte at elevated temperatures (typically 300–350
°C). Currently, the negative electrode or anode is metallic sodium in molten state during battery operation; the positive electrode or cathode can be molten sulfur (Na–S battery) or solid transition metal halides plus a liquid phase secondary electrolyte (e.g., ZEBRA battery). Since the groundbreaking works in the sodium-beta alumina batteries a few decades ago, encouraging progress has been achieved in improving battery performance, along with cost reduction. However, there remain issues that hinder broad applications and market penetration of the technologies. To better the Na-beta alumina technologies require further advancement in materials along with component and system design and engineering. This paper offers a comprehensive review on materials of electrodes and electrolytes for the Na-beta alumina batteries and discusses the challenges ahead for further technology improvement.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Nanocomposites of molybdenum disulfide (MoS2) and poly(ethylene oxide) (PEO) were prepared by the exfoliation/absorption method that involved the hydrolysis of lithiated MoS2 in an aqueous solution ...of PEO. The absorption and subsequent interaction of PEO on the colloidal MoS2 formed a nanocomposite which restacked into layered secondary particles. X-ray diffraction and high resolution TEM indicated that highly disordered nanocomposites were produced when the Lix(PEO)yMoS2 stoichiometry was limited to y < 1. An improvement of greater than 5x in capacity accompanied by high cycle stability and efficiency was observed for the disordered nanocomposites providing a novel approach to utilize low-cost MoS2 and similar materials for a high capacity energy storage system.
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Utilization of carbon dioxide from industrial waste streams offers significant reductions in global carbon dioxide emissions. Solid oxide electrolysis is a highly efficient, high temperature approach ...that reduces polarization losses and best utilizes process heat; however, the technology is relatively unrefined for currently carbon dioxide electrolysis. In most electrochemical systems, the interface between active components are usually of great importance in determining the performance and lifetime of any energy materials application. Here we report a generic approach of interface engineering to achieve active interfaces at nanoscale by a synergistic control of materials functions and interface architectures. We show that the redox-manipulated interfaces facilitate the atomic oxygen transfer from adsorbed carbon dioxide molecules to the cathode lattice that determines carbon dioxide electrolysis at elevated temperatures. The composite cathodes with in situ grown interfaces demonstrate significantly enhanced carbon dioxide electrolysis and improved durability.
Li metal has attracted intense attention due to its high specific capacity, but the dendrite growth during cycling impedes its practical application as a rechargeable anode. To improve the stability ...of the solid‐electrolyte interphase (SEI) on Li metal is the key to develop Li anode with high safety. In native SEI, inorganics act as fast ion channels and organics play the role of soft base with high flexibility to buffer volume change. However, the SEI with inorganics close to Li surface and organics close to electrolyte always leads to a fragile structure, resulting in repeatedly breaking and growing of the surface layer. Artificial SEI is one of the most effective ways to improve interphase stability and extend the cycle life of Li anode. Inorganics such as Li fluoride, Li nitride, Li phosphate and Li alloys have been widely applied in Li protection. In situ chemical reactions, spin coating and doctor blade coating of organics were also conducted to obtain SEI with high lithiophilic functional groups and high elasticity. To fabricate an ideal artificial SEI, organic and inorganic components should be rearranged as a rational structure to possess synergetic effects with both high flexibility and ionic conductivity. This Minireview summarizes the most recent works on artificial SEI and discusses the electrochemical performance of different components as interphase, aiming to inspire the study on designing and fabricating stable Li anode with robust interphase structure.
The next best thing: Artificial solid‐electrolyte interphase (SEI) can improve the performance of Li metal anode by creating surface protection layer, regulating the surface charge distribution, and buffering the electrode expansion during cycling. The components of the SEI show significant influence on the performance of the artificial layer. Artificial SEIs based on inorganic and organic components are summarized and the synergy effect of different components is discussed. SEI composed with inorganic materials that possess fast ion transport and organic materials that provide high flexibility will be a sustainable choice.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Large‐scale electrical energy storage has become more important than ever for reducing fossil energy consumption in transportation and for the widespread deployment of intermittent renewable energy ...in electric grid. However, significant challenges exist for its applications. Here, the status and challenges are reviewed from the perspective of materials science and materials chemistry in electrochemical energy storage technologies, such as Li‐ion batteries, sodium (sulfur and metal halide) batteries, Pb‐acid battery, redox flow batteries, and supercapacitors. Perspectives and approaches are introduced for emerging battery designs and new chemistry combinations to reduce the cost of energy storage devices.
The different applications of energy storage, different technologies, and the cost requirements from the kilowatt to gigawatt scale are compared. Li‐ion batteries have attracted attention for transportation storage, while many other technologies are considered for stationary applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Proton exchange membrane fuel cells have been regarded as the most promising candidate for fuel cell vehicles and tools. Their broader adaption, however, has been impeded by cost and lifetime. By ...integrating a thin layer of tungsten oxide within the anode, which serves as a rapid-response hydrogen reservoir, oxygen scavenger, sensor for power demand, and regulator for hydrogen-disassociation reaction, we herein report proton exchange membrane fuel cells with significantly enhanced power performance for transient operation and low humidified conditions, as well as improved durability against adverse operating conditions. Meanwhile, the enhanced power performance minimizes the use of auxiliary energy-storage systems and reduces costs. Scale fabrication of such devices can be readily achieved based on the current fabrication techniques with negligible extra expense. This work provides proton exchange membrane fuel cells with enhanced power performance, improved durability, prolonged lifetime, and reduced cost for automotive and other applications.
A hierarchically structured nitrogen-doped porous carbon is prepared from a nitrogen-containing isoreticular metal-organic framework (IRMOF-3) using a self-sacrificial templating method. IRMOF-3 ...itself provides the carbon and nitrogen content as well as the porous structure. For high carbonization temperatures (950 °C), the carbonized MOF required no further purification steps, thus eliminating the need for solvents or acid. Nitrogen content and surface area are easily controlled by the carbonization temperature. The nitrogen content decreases from 7 to 3.3 at % as carbonization temperature increases from 600 to 950 °C. There is a distinct trade-off between nitrogen content, porosity, and defects in the carbon structure. Carbonized IRMOFs are evaluated as supercapacitor electrodes. For a carbonization temperature of 950 °C, the nitrogen-doped porous carbon has an exceptionally high capacitance of 239 F g–1. In comparison, an analogous nitrogen-free carbon bears a low capacitance of 24 F g–1, demonstrating the importance of nitrogen dopants in the charge storage process. The route is scalable in that multi-gram quantities of nitrogen-doped porous carbons are easily produced.
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