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Shao Y.,Pacific Northwest National Laboratory | Ding F.,Pacific Northwest National Laboratory | Ding F.,Tianjin Institute of Power Sources | Xiao J.,Pacific Northwest National Laboratory | And 7 more authors.
Advanced Functional Materials | Year: 2013

A Li-air battery could potentially provide three to five times higher energy density/specific energy than conventional batteries and, thus, enable the driving range of an electric vehicle to be comparable to gasoline vehicles. However, making Li-air batteries rechargeable presents significant challenges, mostly related to the materials. Here, the key factors that influence the rechargeability of Li-air batteries are discussed with a focus on nonaqueous systems. The status and materials challenges for nonaqueous rechargeable Li-air batteries are reviewed. These include electrolytes, cathode (electrocatalysts), lithium metal anodes, and oxygen-selective membranes (oxygen supply from air). A perspective for the future of rechargeable Li-air batteries is provided. Rechargeable lithium-air batteries could potentially provide an energy storage capacity of three to five times that of current Li-ion batteries. However, significant material challenges exist for each of its components, among which are electrolytes, cathodes/catalysts, anodes, and oxygen-selective membranes for oxygen supply. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xu W.,Pacific Northwest National Laboratory | Wang J.,Pacific Northwest National Laboratory | Wang J.,Shanghai JiaoTong University | Ding F.,Tianjin Institute of Power Sources | And 5 more authors.
Energy and Environmental Science | Year: 2014

Lithium (Li) metal is an ideal anode material for rechargeable batteries due to its extremely high theoretical specific capacity (3860 mA h g -1), low density (0.59 g cm-3) and the lowest negative electrochemical potential (-3.040 V vs. the standard hydrogen electrode). Unfortunately, uncontrollable dendritic Li growth and limited Coulombic efficiency during Li deposition/stripping inherent in these batteries have prevented their practical applications over the past 40 years. With the emergence of post-Li-ion batteries, safe and efficient operation of Li metal anodes has become an enabling technology which may determine the fate of several promising candidates for the next generation energy storage systems, including rechargeable Li-air batteries, Li-S batteries, and Li metal batteries which utilize intercalation compounds as cathodes. In this paper, various factors that affect the morphology and Coulombic efficiency of Li metal anodes have been analyzed. Technologies utilized to characterize the morphology of Li deposition and the results obtained by modelling of Li dendrite growth have also been reviewed. Finally, recent development and urgent need in this field are discussed. © The Royal Society of Chemistry.

Chong J.,Lawrence Berkeley National Laboratory | Chong J.,Tianjin Institute of Power Sources | Xun S.,Lawrence Berkeley National Laboratory | Song X.,Lawrence Berkeley National Laboratory | And 2 more authors.
Nano Energy | Year: 2013

Li4P2O7-stabilized LiNi0.5Mn1.5O4 was prepared by solid-state synthesis. The material was characterized by X-ray diffraction and high-resolution transition electron microscopy, which showed a coating layer (<10nm) of Li4P2O7 crystallite co-existing with a little Li3PO4 on the LiNi0.5Mn1.5O4/Li4P2O7 primary particles. LiNi0.5Mn1.5O4/Li4P2O7 synthesized at 760°C for 200h had a cubic spinel structure with a space group of Fd3- m; its estimated crystallite size was 527nm. LiNi0.5Mn1.5O4/Li4P2O7 possessed better rate capability and cycling capability. The introduced Li4P2O7 coating layer acted as a solid electrolyte or artificial SEI layer: by separating the active material from the electrolyte, the coating layer prevented the Ni2+/Ni3+ or Ni3+/Ni4+ redox couple from decomposing the electrolyte. Stress/strain from the Ni2+⇌Ni3⇌Ni4+ spinel phase change caused fractures and pulverization of the cycled stoichiometric LiNi0.5Mn1.5O4 crystal surface, especially noticeable for this well-developed micro-sized crystal. The ordered stoichiometric LiNi0.5Mn1.5O4 had more side reactions, led to a quick fading of the material's capacity. Both the Li4P2O7 coating layer and the disordered Fd3- m space group LiNi0.5Mn1.5O4 structure bring benefit to the LiNi0.5Mn1.5O4/Li4P2O7 performance. Thus, the introduced Li4P2O7 coating layer can build an effective solid electrolyte or artificial SEI layer to protect the interface between LiNi0.5Mn1.5O4 and electrolyte. © 2012 Elsevier Ltd.

Chen X.,Pacific Northwest National Laboratory | Li X.,Pacific Northwest National Laboratory | Ding F.,Pacific Northwest National Laboratory | Ding F.,Tianjin Institute of Power Sources | And 8 more authors.
Nano Letters | Year: 2012

A cost-effective and scalable method is developed to prepare a core-shell structured Si/B 4C composite with graphite coating with high efficiency, exceptional rate performance, and long-term stability. In this material, conductive B 4C with a high Mohs hardness serves not only as micro/nano-millers in the ball-milling process to break down micron-sized Si but also as the conductive rigid skeleton to support the in situ formed sub-10 nm Si particles to alleviate the volume expansion during charge/discharge. The Si/B 4C composite is coated with a few graphitic layers to further improve the conductivity and stability of the composite. The Si/B 4C/graphite (SBG) composite anode shows excellent cyclability with a specific capacity of ∼822 mAhg -1 (based on the weight of the entire electrode, including binder and conductive carbon) and ∼94% capacity retention over 100 cycles at 0.3 C rate. This new structure has the potential to provide adequate storage capacity and stability for practical applications and a good opportunity for large-scale manufacturing using commercially available materials and technologies. © 2012 American Chemical Society.

Ding F.,Pacific Northwest National Laboratory | Xu W.,Pacific Northwest National Laboratory | Graff G.L.,Pacific Northwest National Laboratory | Zhang J.,Pacific Northwest National Laboratory | And 11 more authors.
Journal of the American Chemical Society | Year: 2013

Rechargeable lithium metal batteries are considered the "Holy Grail" of energy storage systems. Unfortunately, uncontrollable dendritic lithium growth inherent in these batteries (upon repeated charge/discharge cycling) has prevented their practical application over the past 40 years. We show a novel mechanism that can fundamentally alter dendrite formation. At low concentrations, selected cations (such as cesium or rubidium ions) exhibit an effective reduction potential below the standard reduction potential of lithium ions. During lithium deposition, these additive cations form a positively charged electrostatic shield around the initial growth tip of the protuberances without reduction and deposition of the additives. This forces further deposition of lithium to adjacent regions of the anode and eliminates dendrite formation in lithium metal batteries. This strategy may also prevent dendrite growth in lithium-ion batteries as well as other metal batteries and transform the surface uniformity of coatings deposited in many general electrodeposition processes. © 2013 American Chemical Society.

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