The assignee for this patent, patent number 8632915, is
Reporters obtained the following quote from the background information supplied by the inventors: "Rechargeable batteries comprising metal anodes including, but not limited to, lithium, sodium, and zinc, can be crucial to the development and deployment of many electronic devices, electric vehicles, and other systems requiring energy storage. However, one disadvantage of these rechargeable batteries is the development of surface defects over several charge/discharge cycles. In a particular example, dendrite formation can cause malfunctions such as a short circuiting and/or overheating. Therefore, a need exists for battery anodes having modified surfaces that are not susceptible to the formation of malfunction-inducing surface defects."
In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "The present invention relates to modified surfaces on metal anodes for batteries and to methods for performing such modifications. The modification can include application of a protective coating comprising a nanocomposite that can inhibit formation of surface defects on the anode during charge/discharge cycles.
"In one embodiment, for anodes comprising a metal (M'), the protective coating is characterized by products of chemical or electrochemical dissociation of a nanocomposite containing a polymer and an exfoliated compound (M.sub.a'M.sub.b''X.sub.c). The metal, M', comprises Li, Na, or Zn. The exfoliated compound comprises M' among lamella of M.sub.b''X.sub.c, wherein M'' is Fe, Mo, Ta, W, or V, and X is S, O, or Se.
"The nanocomposite can comprise a substantially disordered arrangement of M.sub.b''X.sub.c lamella. Alternatively, the nanocomposite can comprise a substantially layered arrangement of M.sub.b''X.sub.c lamella. The products of the chemical or electrochemical dissocation of the nanocomposite can comprise at least one of M.sub.r'X.sub.s, M''/M.sub.t', M.sub.u'', and X.sub.v in a matrix of the polymer. In other words, the polymer can form a matrix in which the dissociation products are distributed.
"As used herein, M''/M.sub.t' composite can refer to a chemical interaction between M' and M''. For example, the M' can be accommodated within defect sites of the M''.
"In some embodiments, the polymer further comprises graphene. Preferably, the polymer comprises polyether functionality. As used herein, polyether functionality refers to compounds containing more than one ether (C--O--C) group. Polyether generally refers to polymers which contain the ether functional group in their main chain. The term glycol is reserved for low to medium range molar mass polymers when the nature of the end-group, which is usually a hydroxyl group, still has a substantial effect on the behavior of the polymer. The term 'oxide' or other terms are used for high molar mass polymers where the end-groups no longer affect polymer properties. One example of a polymer having polyether functionality includes, but is not limited to, polyethylene oxide (PEO).
"A preferred embodiment of the present invention comprises a battery having an anode comprising Li and a protective coating over the anode. The protective coating is characterized by products of anodic reduction of a nanocomposite containing a polymer and an exfoliated intercalation compound (Li.sub.aMoS.sub.2) comprising Li among lamella of MoS.sub.2, the products of anodic reduction comprising at least one of Li.sub.2S, S.sub.8, Mo, Li/Mo, and polysuflide in a matrix of the polymer. The polymer can further comprise graphene, in some instances.
"Modification of the metal anode (M'), which comprises Li, Na, or Zn, can involve application of a protective coating. In one embodiment, the method of preparing the protective coating on the battery anode comprises exfoliating an intercalation compound (M.sub.a'M.sub.b''X.sub.c) in a solution. The exfoliation yields a colloid comprising substantially separated lamella of M.sub.b''X.sub.c; wherein M'' is Fe, Mo, Ta, W, or V, and X is S, O, or Se. The method further comprises absorbing a polymer to the lamella of M.sub.b''X.sub.c in the colloid and then forming a nanocomposite by drying the colloid. The nanocomposite comprises the polymer and M' among lamella of M.sub.b''X.sub.c. The lamella can be substantially layered or they can be substantially disordered in arrangement. The nanocomposite is applied to the anode. One way to perform the application can involve contacting the anode and the polymer/colloid mixture prior to drying. The nanocomposite is then chemically or electrochemically dissociated to yield a product comprising at least one of M.sub.r'X.sub.s, M''/M.sub.t', M.sub.u'', and X.sub.v in a matrix of the polymer. In some embodiments, the method can further comprise reacting X.sub.y with dendrites comprising M' formed on surfaces of the anode.
"Preferably the polymer comprises polyether functionality. One example of such a polymer includes, but is not limited to, PEO. In some embodiments, the colloid further comprises graphene.
"In a particular embodiment, M' is Li, M.sub.a'M.sub.b''X.sub.c is Li.sub.aMoS.sub.2, M.sub.b''X.sub.c is MoS.sub.2, M.sub.r'X.sub.s is Li.sub.2S, M''/M.sub.t' is Mo/Li.sub.t, M.sub.u'' is Mo.sub.u, and X.sub.v is S.sub.8 or polysulfide.
"The purpose of the foregoing abstract is to enable the United States Patent and Trademark Office and the public generally, especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
"Various advantages and novel features of the present invention are described herein and will become further readily apparent to those skilled in this art from the following detailed description. In the preceding and following descriptions, the various embodiments, including the preferred embodiments, have been shown and described. Included herein is a description of the best mode contemplated for carrying out the invention. As will be realized, the invention is capable of modification in various respects without departing from the invention. Accordingly, the drawings and description of the preferred embodiments set forth hereafter are to be regarded as illustrative in nature, and not as restrictive."
For more information, see this patent: Lemmon,
Keywords for this news article include: Chemistry, Legal Issues, Electrochemical,
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