As　a　typical　alkaline　earth　metal　carbide,　lithium　carbide　(Li2C2)　has　the　highest　theoretical　specific　capacity　(1400　mAhg(-1))　among　all　the　reported　lithium-containing　cathode　materials　for　lithium　ion　batteries.　Herein,　the　feasibility　of　using　Li2C2　as　a　cathode　material　was　studied.　The　results　show　that　at　least　half　of　the　lithium　can　be　extracted　from　Li2C2　and　the　reversible　specific　capacity　reaches　700　mAhg(-1).　The　C　equivalent　to　C　bond　tends　to　rotate　to　form　C4　(C　equivalent　to　C　center　dot　center　dot　center　dot　C　equivalent　to　C)　chains　during　lithium　extraction,　as　indicated　with　the　first-principles　molecular　dynamics　(FPMD)　simulation.　The　low　electronic　and　ionic　conductivity　are　believed　to　be　responsible　for　the　potential　gap　between　charge　and　discharge,　as　is　supported　with　density　functional　theory　(DFT)　calculations　and　Arrhenius　fitting　results.　These　findings　illustrate　the　feasibility　to　use　the　alkali　and　alkaline　earth　metal　carbides　as　high-capacity　electrode　materials　for　secondary　batteries.