A process for the synthesis of a carbon-deposited alkali metal phosphosilicate cathode material comprising particles, wherein said particles carry, on at least a portion of the particle surface, carbon deposited by pyrolysis, said process comprising: a first dry high-energy milling step performed on precursors of said carbon-deposited alkali metal phosphosilicate prior to a first solid-state thermal reaction, wherein said first solid-state thermal reaction produces a first solid-state thermal reaction product; and a second dry high-energy milling step performed on said product prior to a second solid-state thermal reaction, wherein said precursors comprise at least one source compound of an alkali metal, at least one source compound of a metal M, where M is Fe and/or Mn; at least one source compound of a metal M', where M' is a 2+ or more metal in the carbon-deposited alkali metal phosphosilicate; at least one source compound of phosphorus, if the element P is not present in another source compound; at least one source compound of silicon (Si), if the element Si is not present in another source compound, and at least one source of carbon, wherein said source compound of M' is a source compound a metal selected from the group consisting of Zr 4+, Ti 4+, Nb 4+, Mo 4+, Ge 4+, Ce 4+ and Sn 4+, and/or a source compound of a metal selected from the group consisting of Al 3+, Y 3+, Nb 3+, Ti 3+, Ga 3+, Cr 3+ and V 3+, and/or a source compound of a metal selected from the group consisting of Ta 5+ and Nb 5+, and/or a source compound of a metal selected from the group consisting of Zn 2+ and Ca 2+; wherein pyrolysis of the at least one source of carbon and deposition of the carbon onto the precursors and/or the alkali metal phosphosilicate occurs during the first thermal step and/or the second thermal step wherein the first solid state thermal step is operated at a temperature selected from the range of temperatures between 200°C and 600°C wherein the second solid state thermal step is operated at a temperature selected from the range of temperatures between 400°C and 800°C wherein the first and second solid state thermal steps are performed under an inert or reductive atmosphere wherein said atmosphere is optionally humidified wherein said first and second high energy milling steps are performed during a time period selected from between 5 minutes and 4 hours and wherein the high-energy milling steps produce a substantially amorphous product and the second thermal reaction produces a substantially crystalline product. a first dry high-energy milling step performed on precursors of said carbon-deposited alkali metal phosphosilicate prior to a first solid-state thermal reaction, wherein said first solid-state thermal reaction produces a first solid-state thermal reaction product; and a second dry high-energy milling step performed on said product prior to a second solid-state thermal reaction, wherein said precursors comprise at least one source compound of an alkali metal, at least one source compound of a metal M, where M is Fe and/or Mn; at least one source compound of a metal M', where M' is a 2+ or more metal in the carbon-deposited alkali metal phosphosilicate; at least one source compound of phosphorus, if the element P is not present in another source compound; at least one source compound of silicon (Si), if the element Si is not present in another source compound, and at least one source of carbon, wherein said source compound of M' is a source compound a metal selected from the group consisting of Zr 4+, Ti 4+, Nb 4+, Mo 4+, Ge 4+, Ce 4+ and Sn 4+, and/or a source compound of a metal selected from the group consisting of Al 3+, Y 3+, Nb 3+, Ti 3+, Ga 3+, Cr 3+ and V 3+, and/or a source compound of a metal selected from the group consisting of Ta 5+ and Nb 5+, and/or a source compound of a metal selected from the group consisting of Zn 2+ and Ca 2+; wherein pyrolysis of the at least one source of carbon and deposition of the carbon onto the precursors and/or the alkali metal phosphosilicate occurs during the first thermal step and/or the second thermal step wherein the first solid state thermal step is operated at a temperature selected from the range of temperatures between 200°C and 600°C wherein the second solid state thermal step is operated at a temperature selected from the range of temperatures between 400°C and 800°C wherein the first and second solid state thermal steps are performed under an inert or reductive atmosphere wherein said atmosphere is optionally humidified wherein said first and second high energy milling steps are performed during a time period selected from between 5 minutes and 4 hours and wherein the high-energy milling steps produce a substantially amorphous product and the second thermal reaction produces a substantially crystalline product.