Abstract: 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 formulaLi.sub.1 D.sub.x/b Mn.sub.2-x O.sub.4+.delta.where(i) x is a number such that 0.ltoreq.x<0,33;(ii) .delta. is a number such that 0.ltoreq..delta.<0,5, with the values of x and .delta. being such that the oxidation state N of the manganese cation is 3,5<N<4,0;(iii) D is a mono- or multi-valent metal cation; and(iv) b is the oxidation state of D.An electrolyte is also located in the cell housing. The cell housing, electrolyte and cathode are arranged to permit a charging potential to be applied to the cell to cause lithium from the cathode to form, in the cell housing, at least part of the anode, while the electrolyte couples the cathode electrochemically to the anode, and insulates it electronically therefrom.

Abstract: 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.

Abstract: The invention provides a hydrogen manganese oxide compound. It has manganese cations and oxygen anions arranged in a framework having a hollandite-type structure and defining channels. Cations in the channels are confined to manganse, hydrogen and/or lithium cations. The ionic ratios of lithium:manganese cations and of hydrogen:manganese cations are respectively at most 0.05:1 and at least 0.01:1.00. The invention also provides a method of making said compound; a lithium manganese oxide compound derived from said hydrogen manganese oxide compound and a method of synthesising it therefrom; and electrochemical cells employing said hydrogen manganese oxide and lithium manganese oxide compounds as active cathode materials.

Abstract: The invention provides a process for the production of 3-(1-amino-1,3-dicarboxy-3-hydroxy-but-4-yl) indole and certain salts and internal condensation products thereof. An unsaturated indolyl ester is reacted with ethylchloro(hydroxyimino)acetate in the presence of triethylamine in an organic solvent to cause a 1,3-dipolar addition reaction to form a di-ester. The di-ester is saponified to form a di-acid which di-acid is then reduced to form either the product indole or a salt thereof.