Abstract:
A battery electrode comprises an electrically conductive substrate having an electrochemically active electrode composition supported thereupon. The composition includes an active material capable of reversibly alloying with lithium, which material shows a volume change upon such reversible alloying. The composition includes a buffering agent which accommodates the volume change in the active material and minimizes mechanical strain in the composition. The active composition may further include materials such as carbon. The active material may comprise silicon, aluminum, antimony, antimony oxides, bismuth, bismuth oxides, tin, tin oxides, chromium, chromium oxides, tungsten, and tungsten oxides or lithium alloys of the foregoing. The buffering agent may comprise a metal or a metal oxide or lithium alloys of the foregoing. Also disclosed are batteries which incorporate these electrodes, methods for the fabrication of the electrodes and methods for the fabrication and operation of the batteries.
Abstract:
A composite material includes first phase which comprises Li x M y (PO 4 ) z wherein M is at least one metal, y and z are independently 0, and x is less than or equal to 1. The material includes a second phase which has an electronic and/or lithium ion conductivity greater than that of the first phase. The material is prepared by heating a starting mixture which includes lithium, iron, a phosphate ion, and a catalyst in a reducing atmosphere. Also disclosed are electrodes which incorporate the material and batteries which utilize those electrodes as cathodes.
Abstract translation:复合材料包括第一相和第二相,所述第一相包含Li M y SUB>(PO 4 SUB>) z SUB>,其中M至少为 一种金属,y和z独立地为0,并且x小于或等于1.该材料包括具有比第一相的电子和/或锂离子电导率大的第二相。 该材料通过在还原气氛中加热包含锂,铁,磷酸根离子和催化剂的起始混合物来制备。 还公开了结合利用这些电极作为阴极的材料和电池的电极。
Abstract:
A composite material includes a first phase which is present in the form of a plurality of particles comprised of a material having the general formula Li x M y (PO 4 ) z wherein M is at least one metal, x is equal to or greater than zero, and y and z are each, independently, greater than zero. The material includes a second phase which is at least partially present in the form of a plurality of elongated filaments which extend between and establish electrical contact with at least two particles of the first phase. The filaments are comprised of a material which includes phosphorus and at least one of the at least one metal M. The material of the second phase has an electrical conductivity which is greater than the electrical conductivity of the material of the first phase. Also disclosed are methods for manufacturing the material. The material has utility as an electrode material for devices such as lithium batteries.
Abstract:
A proton exchange membrane for a fuel cell is prepared from a polyimidazole polymer having the formula: (I), wherein R1-R3 are independently H, a halogen, an alkyl or a substituted alkyl, X1 and X2 are independently or an electron withdrawing group such as CN. The membrane may be doped to alter its conductivity. The membrane may be prepared from a copolymer of the polyimidazole. Also disclosed is a fuel cell incorporating the membrane.
Abstract:
A battery electrode comprises an electrically conductive substrate having an electrochemically active electrode composition supported thereupon. The composition includes an active material capable of reversibly alloying with lithium, which material shows a volume change upon such reversible alloying. The composition includes a buffering agent which accommodates the volume change in the active material and minimizes mechanical strain in the composition. The active composition may further include materials such as carbon. The active material may comprise silicon, aluminum, antimony, antimony oxides, bismuth, bismuth oxides, tin, tin oxides, chromium, chromium oxides, tungsten, and tungsten oxides or lithium alloys of the foregoing. The buffering agent may comprise a metal or a metal oxide or lithium alloys of the foregoing. Also disclosed are batteries which incorporate these electrodes, methods for the fabrication of the electrodes and methods for the fabrication and operation of the batteries.
Abstract:
A composite electrode material is fabricated from a first electroactive material which, when incorporated into a cathode of a rechargeable battery, manifests a first mean voltage, a first energy density and a first high cutoff voltage cycle life; and a second electroactive material which, when incorporated into a cathode of the rechargeable battery, manifests a second mean voltage which is less than the first mean voltage, a second energy density which is less than the first energy density, and a second high voltage cutoff cycle life which is greater than the first cycle life. The composite material is characterized in that when it is incorporated into a cathode of the rechargeable battery, it manifests at least one of: a third mean voltage which is greater than the second mean voltage, a third energy density which is greater than the second energy density, and a third high cutoff voltage cycle life which is greater than the first cycle life. The rate performance of the second material, when incorporated into a rechargeable battery, may be greater than the rate performance of the first material when incorporated into the rechargeable battery, and the rate performance of the composite material^ when incorporated into a cathode of the rechargeable battery, is greater than the first, rate performance. The composite material may include a simple mixture of particles of the first and second materials, or may comprise a complex structure such as a core/shell structure wherein the second material covers a portion of the surface of particles of the first material. Also disclosed herein are electrodes which incorporate the material, batteries which incorporate the electrodes, and methods for making the foregoing.
Abstract:
Materials useful as electrodes for lithium batteries have very good electronic and ionic conductivities. They are fabricated from a starting mixture which includes a metal, a phosphate ion, and an additive which enhances the transport of lithium ions in the resultant material. The mixture is heated in a reducing environment to produce the material. The additive may comprise a pentavalent metal or a carbon. In certain embodiments the material is a two-phase material. Also disclosed are electrodes which incorporate the materials and lithium batteries which incorporate those electrodes.
Abstract:
A composite material includes a first phase which is present in the form of a plurality of particles comprised of a material having the general formula Li x M y (PO 4 ) z wherein M is at least one metal, x is equal to or greater than zero, and y and z are each, independently, greater than zero. The material includes a second phase which is at least partially present in the form of a plurality of elongated filaments which extend between and establish electrical contact with at least two particles of the first phase. The filaments are comprised of a material which includes phosphorus and at least one of the at least one metal M. The material of the second phase has an electrical conductivity which is greater than the electrical conductivity of the material of the first phase. Also disclosed are methods for manufacturing the material. The material has utility as an electrode material for devices such as lithium batteries.
Abstract translation:复合材料包括第一相和第二相,第一相以多种颗粒的形式存在,所述多个颗粒由具有通式Li x M y SUB>(PO 4 其中M是至少一种金属,x等于或大于零,并且y和z各自独立地大于零。 所述材料包括第二相,所述第二相至少部分以多个细长丝的形式存在,所述细丝在所述第一相的至少两个颗粒之间延伸并与其建立电接触。 长丝由包含磷和至少一种金属M中的至少一种的材料构成。第二相的材料具有比第一相的材料的电导率更大的电导率。 还公开了用于制造该材料的方法。 该材料可用作锂电池等器件的电极材料。
Abstract:
A catalyst is synthesized by a method in which a catalytic metal such as platinum or another noble metal is dispersed onto support member. A transition metal macrocycle is also adsorbed onto the support, and the support is heat treated so as to at least partially pyrolyze the macrocycle and anchor the transition metal to the support. The catalytic metal is alloyed with the transition metal either during the pyrolysis step, or in a separate step. The catalyst has significant utility in a variety of applications including use as an oxygen reduction catalyst in fuel cells.
Abstract:
A composite material having utility as a cathode material for a lithium ion battery includes a first component which is a metal phosphate and a second component which is a metal nitride, a metal oxynitride, or a mixture of the two. The second component is coated on, or dispersed through the bulk of, the first component. The metal phosphate may be a lithiated metal phosphate and may be based upon one or more transition metals. Also disclosed is a method for preparing the material as well as electrodes fabricated from the material and lithium ion cells which include such electrodes.