Patent•
Mixed ionic electronic conductor coatings for redox electrodes
01 Sep 1998-
TL;DR: In this article, a mixed ionic electronic conductor (MIEC) is applied to the surface of a redox electrode to mitigate plugging by precipitated discharge products, which allows for rapid removal of discharge product precipitates from redox electrodes since it is capable of conducting both electrons and ions.
Abstract: Disclosed is a redox electrode for a battery cell that has a coating to mitigate plugging by precipitated discharge products. The coating comprises a mixed ionic electronic conductor (MIEC) which is applied to the surface of a redox electrode. The presence of the MIEC coating allows for rapid removal of discharge product precipitates from redox electrodes since it is capable of conducting both electrons and ions. As a result, the chemical action necessary to remove such precipitates may take place on both the electrolyte side of the precipitate and at the precipitate/electrode interface. MIEC coatings in accordance with the present invention may be composed of any suitable material having ionic conductivity for a metal ion in a negative electrode with which the redox electrode is to be paired in a battery cell, and reversible redox capacity. Examples include titanium sulfide (TiS 2 ), iron sulfide (FeS 2 ), and cobalt oxides.
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Patent•
08 Oct 2004
TL;DR: Active metal and active metal intercalation electrode structures and battery cells having ionically conductive protective architecture including an active metal (e.g., lithium) conductive impervious layer separated from the electrode (anode) by a porous separator impregnated with a non-aqueous electrolyte (anolyte) are discussed in this article.
Abstract: Active metal and active metal intercalation electrode structures and battery cells having ionically conductive protective architecture including an active metal (e.g., lithium) conductive impervious layer separated from the electrode (anode) by a porous separator impregnated with a non-aqueous electrolyte (anolyte). This protective architecture prevents the active metal from deleterious reaction with the environment on the other (cathode) side of the impervious layer, which may include aqueous or non-aqueous liquid electrolytes (catholytes) and/or a variety electrochemically active materials, including liquid, solid and gaseous oxidizers. Safety additives and designs that facilitate manufacture are also provided.
278 citations
Patent•
14 Oct 2003
TL;DR: In this article, the properties of different ionic conductors are combined in a composite material that has the desired properties of high overall ionicity and chemical stability towards the anode, the cathode and ambient conditions encountered in battery manufacturing.
Abstract: Disclosed are ionically conductive composites for protection of active metal anodes and methods for their fabrication. The composites may be incorporated in active metal negative electrode (anode) structures and battery cells. In accordance with the invention, the properties of different ionic conductors are combined in a composite material that has the desired properties of high overall ionic conductivity and chemical stability towards the anode, the cathode and ambient conditions encountered in battery manufacturing. The composite is capable of protecting an active metal anode from deleterious reaction with other battery components or ambient conditions while providing a high level of ionic conductivity to facilitate manufacture and/or enhance performance of a battery cell in which the composite is incorporated.
220 citations
Patent•
08 Oct 2004
TL;DR: In this article, Li/water, Li/air and Li/metal hydride cells, components, configurations and fabrication techniques are provided. But they do not consider the use of ionic anodes.
Abstract: Alkali (or other active) metal battery and other electrochemical cells incorporating active metal anodes together with aqueous cathode/electrolyte systems. The battery cells have a highly ionically conductive protective membrane adjacent to the alkali metal anode that effectively isolates (de-couples) the alkali metal electrode from solvent, electrolyte processing and/or cathode environments, and at the same time allows ion transport in and out of these environments. Isolation of the anode from other components of a battery cell or other electrochemical cell in this way allows the use of virtually any solvent, electrolyte and/or cathode material in conjunction with the anode. Also, optimization of electrolytes or cathode-side solvent systems may be done without impacting anode stability or performance. In particular, Li/water, Li/air and Li/metal hydride cells, components, configurations and fabrication techniques are provided.
196 citations
Patent•
03 Feb 2004
TL;DR: In this paper, ionically conductive membranes for protection of active metal anodes and methods for their fabrication are described. But the authors do not specify how to construct the membrane.
Abstract: Disclosed are ionically conductive membranes for protection of active metal anodes and methods for their fabrication. The membranes may be incorporated in active metal negative electrode (anode) structures and battery cells. In accordance with the invention, the membrane has the desired properties of high overall ionic conductivity and chemical stability towards the anode, the cathode and ambient conditions encountered in battery manufacturing. The membrane is capable of protecting an active metal anode from deleterious reaction with other battery components or ambient conditions while providing a high level of ionic conductivity to facilitate manufacture and/or enhance performance of a battery cell in which the membrane is incorporated.
160 citations
Patent•
20 Dec 2002
TL;DR: In this article, compositions and methods for alleviating the problem of reaction of lithium or other alkali or alkaline earth metals with incompatible processing and operating environments by creating an ionically conductive chemical protective layer on the lithium surface were discussed.
Abstract: Disclosed are compositions and methods for alleviating the problem of reaction of lithium or other alkali or alkaline earth metals with incompatible processing and operating environments by creating an ionically conductive chemical protective layer on the lithium or other reactive metal surface. Such a chemically produced surface layer can protect lithium metal from reacting with oxygen, nitrogen or moisture in ambient atmosphere thereby allowing the lithium material to be handled outside of a controlled atmosphere, such as a dry room. Production processes involving lithium are thereby very considerably simplified. One example of such a process is the processing of lithium to form negative electrodes for lithium metal batteries.
146 citations
References
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TL;DR: In this article, Li/5M S cells were characterized with regard to capacity, rate, and rechargeability, showing that 75% cathode utilization is possible at 4 mA/cm2 (C/3-C/4 rate).
Abstract: Prototype cells of the configuration Li/~5M S as , THF, have been characterized with regard to capacity, rate, and rechargeability. Virtually 100% of the theoretical capacity could be realized at 50°C at rates below 1.0 mA/cm2. In high rate cell configurations, 75% cathode utilization is possible at ~4 mA/cm2 (C/3–C/4 rate). The capacities at high rate are enhanced by Lewis acids, although the ultimate cause of rate limitation is passivation of the current collector by discharge products. The self‐discharge rates of Li in contact with 4–5M S (as ) solutions reveal capacity losses of 0.5%/day at 25°C to 4.4%/day at 71°C. Based on the experimental results, a practical energy density of ~300 W‐hr kg−1 is possible using a standard cell design. Results on the battery's rechargeability are briefly reviewed.
582 citations
TL;DR: The redox processes of a glassy carbon electrode in THF were studied by programmed cyclic voltammetry in the range of +1300 to −2000 mV at sweep rates of 2-200 mV/s.
Abstract: The redox processes of at a glassy carbon electrode in THF was studied by programmed cyclic voltammetry in the range of +1300 to −2000 mV (vs. polysulfide reference electrode) at sweep rates of 2–200 mV/s. One anodic and up to three cathodic peaks were detected. The anodic peak seems to result from the oxidation of all PS's through the same intermediate to elemental sulfur. The first cathodic peak is caused by the reduction of all PS to in a diffusion controlled reaction. The second reduction peak most likely arises from the reduction of to . This is apparently preceded by a chemical step. The third reduction peak is caused by the reduction of to or S2− or a mixture of both in a diffusion‐controlled reaction. The high Tafel slope of the third peak apparently results from passivation of the electrode by the precipitation of and .
479 citations
TL;DR: In this paper, the development and the electrochemistry of low-rate laboratory prototype Li/S button cells is described. The cell consists of a lithium anode, a porous catalytic current collector which is loaded with sulfur, and an organic solvent containing lithium polysulfide.
365 citations
Patent•
03 Oct 1995
TL;DR: In this paper, positive electrodes containing active-sulfur-based composite electrodes are provided in a manner allowing at least about 10% of the active sulfur to be available for electrochemical reaction.
Abstract: Disclosed are positive electrodes containing active-sulfur-based composite electrodes. The cells include active-sulfur, an electronic conductor, and an ionic conductor. These materials are provided in a manner allowing at least about 10% of the active-sulfur to be available for electrochemical reaction. Also disclosed are methods for fabricating active-sulfur-based composite electrodes. The method begins with a step of combining the electrode components in a slurry. Next, the slurry is homogenized such that the electrode components are well mixed and free of agglomerates. Thereafter, before the electrode components have settled or separated to any significant degree, the slurry is coated on a substrate to form a thin film. Finally, the coated film is dried to form the electrode in such a manner that the electrode components do not significantly redistribute.
350 citations
TL;DR: In this article, the formation of polysulfide chains in certain aprotic media can be accomplished either by electrochemical reduction of S 8 or by direct in situ reaction with Li or Li 2 S.
331 citations