Compared　with　organic　electrode　materials　that　are　used　for　lithium　ion　batteries　that　are　constructed　using　small　organic　molecules,　polymer　electrode　materials　have　a　better　cycling　stability,　which　may　be　due　to　their　stable　long　chain　structure,　and　currently,　the　mechanism　of　energy　storage　has　not　been　thoroughly　elucidated.　In　this　study,　dispersion-corrected　density　functional　theory　(DFT-D2)　was　used　to　explore　the　charge/discharge　process　of　polyimide,　which　is　an　organic　polymer　electrode　material　that　could　be　used　in　Li-ion　batteries.　The　calculated　potentials　of　PI-1　(polyimide-1)　and　PI-2　(polyimide-2)　are　2.03　and　2.07　V,　respectively,　and　they　significantly　agree　with　experimental　values,　which　implies　that　DFT-D2　is　a　powerful　method　to　investigate　polymer　electrodes　for　use　in　lithium　ion　batteries.　The　calculated　potential　of　pyromellitimide　(DPI)　is　1.79　V,　and　DPI　is　a　novel　electrode　material　that　has　not　been　reported　to　date.　For　each　of　the　three　polyimides,　lithium　ions　do　not　diffuse　along　the　polymer　chains　but　diffuse　in　the　vertical　direction,　and　the　migration　barriers　of　PI-1,　PI-2,　and　DPI　are　0.47,　0.84,　and　0.088　eV,　respectively;　thus,　they　have　good　ionic　conductivities　(beyond　PI-2).　Although　the　calculated　band　gaps　of　the　three　polyimides　are　all　approximately　1.0　eV,　the　effective　electron　(or　hole)　masses　are　too　large,　which　may　limit　their　electronic　conductivities　and　rate　performances.　The　calculated　results　show　that　polyimides　are　potential　Li-ion　electrode　materials,　and　this　theoretical　method　could　be　applied　to　design　novel　polymer　electrode　materials.　(C)　2018　Elsevier　B.V.　All　rights　reserved.