Electrode compositions and alkali metal batteries comprising same

A process for preparing a composition-of-matter comprising a plurality of particles, said particles comprising Li2S, wherein in at least a portion of said particles, each particle is being encapsulated within a volume enclosed by a shell or matrix which conducts lithium cations, the process comprising:

• i) providing particles comprising said Li2S;
• and
• ii) coating said particles with a conductor of lithium cations, thereby forming said shell or matrix, wherein said conductor of lithium cations is selected from the group consisting of lithium carbonate, lithium sulfate, a metal disulfide comprising lithium, and any combination thereof, said coating comprising:
• mixing said particles comprising said Li2S with particles of said conductor of lithium cations, and optionally with additional particles of an electron conductor, to obtain a mixture;
• and
• subjecting said mixture to a heat treatment which effects sintering of particles in said mixture and to a heat treatment which effects melting of said particles of said conductor of lithium cations and/or said additional particles of an electron conductor, but not melting of said particles comprising said Li2S, to thereby form said shell or matrix.