Abstract: A method of operating a rechargeable sodium ion cell, wherein the cell comprises an anode material which is a disordered carbon and a nickel-containing sodium oxide cathode material comprises: in a formation charge phase, charging the cell to a first voltage at which sodium is irreversibly liberated from the cathode material; and in a subsequent charge-discharge cycle, charging the cell to a second voltage lower than the first voltage. The voltage to which the cell is charged in the formation charge phase may be selected such that the amount of sodium irreversibly liberated from the cathode material in the formation charge phase substantially equals the amount of sodium deposited in a surface electrolyte layer on the anode in the formation charge phase.

Abstract: The present invention is directed to an electrode comprising one or more sodium-containing transition metal silicate compounds of the formula: AaM1bM2cXdOe wherein A comprises sodium or a mixture of sodium with lithium and/or potassium M1 comprises one or more transition metals, wherein M1 is capable of undergoing oxidation to a higher oxidation state, M2 comprises one or more non transition metals and/or metalloids, X comprises at least 40 mol % silicon, a is >0, b is >0 c is ?0, d is ?1, e is ?2, wherein the values of a, b, c, d, and e are selected to maintain the electroneutrality of the compound; and further wherein the one or more sodium-containing transition metal silicate compounds does not include Na2MnSiO4.

Abstract: One aspect of the present invention provides a method comprising: manufacturing a sodium ion secondary cell having an anode and a cathode, the anode comprising a negative electrode active material comprising disordered carbon on an anode substrate, and the cathode comprising a comprising a nickel-containing sodium oxide positive electrode active material on a cathode substrate; and in a cycling phase, charging the cell to a first voltage; wherein the ratio of the mass of the negative electrode active material to the mass of the positive electrode active material is greater than 0.37 and is less than 1.2.

Abstract: A method of operating a rechargeable sodium ion cell, wherein the cell comprises an anode material which is a disordered carbon and a nickel-containing sodium oxide cathode material comprises: in a formation charge phase, charging the cell to a first voltage at which sodium is irreversibly liberated from the cathode material; and in a subsequent charge-discharge cycle, charging the cell to a second voltage lower than the first voltage. The voltage to which the cell is charged in the formation charge phase may be selected such that the amount of sodium irreversibly liberated from the cathode material in the formation charge phase substantially equals the amount of sodium deposited in a surface electrolyte layer on the anode in the formation charge phase.

Abstract: The present invention is directed to an electrode comprising one or more sodium-containing transition metal silicate compounds of the formula: AaM1bM2cXdOe wherein A comprises sodium or a mixture of sodium with lithium and/or potassium M1 comprises one or more transition metals, wherein M1 is capable of undergoing oxidation to a higher oxidation state, M2 comprises one or more non transition metals and/or metalloids, X comprises at least 40 mol % silicon, a is >0, b is >0 c is ?0, d is ?1, e is ?2, wherein the values of a, b, c, d, and e are selected to maintain the electroneutrality of the compound; and further wherein the one or more sodium-containing transition metal silicate compounds does not include Na2MnSiO4.

Abstract: A macroporous sodium transition metal silicate material includes a composition represented by AaM1bM2cXdOe, wherein A is sodium or a mixture of sodium with lithium and/or potassium; M1 is one or more transition metals; M2 is one or more metals and/or metalloids; X is silicon or a mixture containing silicon and one or more elements selected from phosphorus, boron and aluminium; a is >0; b is >0; c is ?0; d is ?1; and e is ?2. A method of forming the macroporous sodium transition metal silicate material includes mixing one or more transition metal precursor materials in a solvent to form a transition metal mixture; adding one or more silicate precursors to the transition metal mixture to form a precursor mixture; raising the pH of the precursor mixture to form a precipitate; stirring the mixture; aging and drying the mixture; washing the mixture; and drying.