An　integrated　model　of　thermodynamics　and　first-principles　calculation　was　developed.　The　Gibbs　free　energy　of　the　nanograin　boundaries　in　the　nanocrystalline　alpha-Li2C2　system　was　calculated　as　a　function　of　temperature　and　grain　size,　and　the　electronic　structures　at　the　surface　and　in　the　interior　of　the　nanograin　were　analyzed.　The　modeling　results　show　that　when　the　grain　size　is　smaller　than　a　critical　value,　the　nanocrystalline　alpha-Li2C2　has　higher　thermodynamic　stability　than　the　conventional　polycrystalline　counterpart.　The　analysis　of　the　electronic　structure　indicates　that　the　nanocrystalline　alpha-Li2C2　can　have　good　performance　in　the　lithiation/delithiation　processes.　The　structure　of　the　delithiated　phase　and　the　optimal　theoretical　capacity　were　further　predicted　by　the　model.　On　the　other　hand,　the　conventional　polycrystalline　and　nanocrystalline　alpha-Li2C2　were　prepared　and　the　electrochemical　tests　were　performed.　As　compared　with　the　conventional　polycrystalline　alpha-Li2C2,　the　nanocrystalline　alpha-Li2C2　has　a　larger　discharge　capacity　and　much　higher　cycling　stability　as　the　cathode　material,　which　confirms　the　model　predictions.　The　results　of　model　prediction　and　experimental　identification　propose　that　the　nanocrystalline　alpha-Li2C2　is　a　promising　cathode　material　for　lithium-ion　batteries.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.