Recycling　of　spent　lithium-ion　batteries　(LIBs)　cathode　materials　has　become　a　hot　research　area　owing　to　limited　resources,　environmental　problems,　and　strong　global　demand　for　LIBs　raw　materials.　However,　among　multiple　types　of　spent　LIBs　cathode　materials,　the　recycling　of　spent　xLi2MnO3·(1-x)LiMO2　cathode　materials　has　not　been　studied　and　remains　challenging.　Herein,　a　green　and　efficient　process　has　been　developed　for　the　simultaneous　recovery　of　Li,　Ni,　and　Mn　from　spent　xLi2MnO3·(1-x)LiMO2　cathode　materials　by　an　ammonium　sulfate　roasting　method.　At　optimal　conditions　of　the　roasting　temperature　of　450　°C,　the　(NH4)2SO4-to-spent　xLi2MnO3·(1-x)LiMO2　mass　ratio　of　3:1,　and　the　roasting　time　of　24　min,　the　spent　xLi2MnO3·(1-x)LiMO2　phase　was　completely　destroyed　and　converted　into　water-soluble　metal-ammine-sulfates　and　metal-sulfates,　resulting　in　that　99.41%　Li,　98.67%　Ni,　and　98.61%　Mn　were　rapidly　extracted.　Furthermore,　possible　conversion　mechanisms　and　the　kinetics　for　the　roasting　process　were　both　investigated　in　detail,　combined　thermodynamics,　DSC-TG,　macro–micro　scale　analyses　and　DFT　calculations.　Finally,　Mn　as　high-purity　MnSO4　products　with　a　purity　of　99.98%,　and　Li　and　Ni　as　Li2SO4-NiSO4　mixture　products,　were　efficiently　recovered　via　(NH4)2SO3　precipitation,　oxidation　leaching,　extraction　and　stripping,　and　evaporative　crystallization.　Compared　with　other　current　recovery　process,　this　work　shows　better　economic　and　environmental　benefits,　while　maintaining　the　considerable　Li,　Ni,　and　Mn　extraction　yields,　which　is　expected　for　the　recycling　of　spent　xLi2MnO3·(1-x)LiMO2　cathode　materials　in　the　future.　©　2023