Technology Finance Corporation (proprietary) Limited

Technology Finance Corporation (prop.) Ltd

Rosalind J Gummow

Michael M Thackeray

Ernest E Ferg

An electrochemical cell comprises as an anode, a lithium transition metal oxide or sulphide compound which has a [B]Xspinel-type framework structure of an A[B]Xspinel wherein A and B are metal cations selected from Li, Ti, V, Mn, Fe and Co, X is oxygen or sulphur, and n&#x2212; refers to the overall charge of the structural unit [B]Xof the framework structure. The transition metal cation in the fully discharged state has a mean oxidation state greater than +3 for Ti, +3 for V, +3.5 for Mn, +2 for Fe and +2 for Co. The cell includes as a cathode, a lithium metal oxide or sulphide compound. An electrically insulative lithium containing liquid or polymeric electronically conductive electrolyte is provided between the anode and the cathode.

Electrochemical cell

An electrochemical cell comprises as an anode, a lithium transition metal oxide or sulphide compound which has a [B]Xspinel-type framework structure of an A[B]Xspinel wherein A and B are metal cations selected from Li, Ti, V, Mn, Fe and Co, X is oxygen or sulphur, and n&#x2212; refers to the overall charge of the structural unit [B]Xof the framework structure. The transition metal cation in the fully discharged state has a mean oxidation state greater than +3 for Ti, +3 for V, +3,5 for Mn, +2 for Fe and +2 for Co. The cell includes as a cathode, a lithium metal oxide or sulphide compound. An electrically insulative lithium containing liquid or polymeric electronically conductive electrolyte is provided between the anode and the cathode.

An electrochemical cell comprises as an anode, a lithium transition metal oxide or sulphide compound which as a [B]Xspinel-type framework structure of an A[B]Sspinel wherein A and B are metal cations selected from Li, Ti, V, Mn, Fe and Co, X is oxygen or sulphur, and n&#x2212; refers to the overall charge of the structural unit [B]Xof the framework structure. The transition metal cation in the fully discharged state has a mean oxidation state greater than +3 for Ti, +3 for V, +3.5 for Mn, +2 for Fe and +2 for Co. The cell includes as a cathode, a lithium metal oxide or sulphide compound. An electrically insulative lithium containing liquid or polymeric electronically conductive electrolyte is provided between the anode and the cathode.

An electrochemical cell comprises a cell housing, and a cathode located in the cell housing. The cathode comprises at least one electrochemically active compound of lithium, manganese and oxygen. The compound has a spinel-type structure and has the general formula

An electrochemical cell precursor and method of making it are provided; and a method of making an electrochemical cell and electrodes therefor. The cell precursor comprises a housing having an anode terminal exposed to its interior. An electrolyte is in the housing for electrochemically coupling the terminal to a cathode in the housing, a cathode precursor being in the housing. The cell precursor is made by loading the electrolyte and cathode precursor into the housing, such that the anode is electrochemically coupled by the electrolyte to the cathode precursor, being electrochemically insulated therefrom. The cell and its electrodes are made by subjecting the cell precursor to a charging potential whereby the cathode precursor acts as a cathode. The cathode precursor comprises at least one compound of lithium, manganese and oxygen, which falls in a defined area of an isothermal slice of the Li-Mn-O phase diagram at 20.degree. C.

The invention provides an essentially layered lithium transition metal oxide compound and a method of making it. It comprises lithium cations, transition metal cations T and oxygen anions, the transition metal cations T having an average valency of from +3 to +4. It has its O anions arranged in layers in a substantially cubic-close-packed arrangement, with its Li cations being arranged in layers and its T cations occupying octahedral sites and being arranged in layers. Each layer of the Li cations is sandwiched between two layers of the O anions and each said layer of O anions is sandwiched between a said layer of Li cations and a layer of the T cations. 75%-99.8% of the T cations in the compound are located in the layers of T cations, and the remainder of the T cations are located in the layers of Li cations, the T cations being selected from Co cations and mixtures of Co and Ni cations.

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Pretoria, South Africa

Rosalind J Gummow