The　electronic　properties　and　different　metal　ion　(Li,　Na,　Mg)　storage　capabilities　of　the　two-dimensional　(2D)　Ti3N2　monolayer　and　its　Ti3N2X2　derivatives　(X　=　O,　F,　and　OH)　as　anode　materials　in　rechargeable　batteries　have　been　systematically　investigated　by　density　functional　theory　(DFT)　computations.　Results　show　that　the　bare　Ti3N2　and　terminated　monolayers　in　their　most　stable　configurations　are　all　metallic　before　and　after　metal　ion　adsorption.　The　relatively　low　diffusion　barriers　on　the　bare　Ti3N2　monolayer　were　also　confirmed,　which　implies　faster　charge　and　discharge　rates.　With　respect　to　storage　capacity,　a　high　theoretical　capacity　of　1874　mA　h　g-1　can　be　provided　by　the　Ti3N2　monolayer　for　Mg　due　to　its　multilayer　adsorption　and　two-electron　reaction.　The　existence　of　functional　groups　is　proven　to　be　unfavorable　to　metal　ion　migration　and　will　decrease　the　corresponding　storage　capacities,　which　should　be　avoided　in　experiments　as　much　as　possible.　These　excellent　performances　suggest　that　the　bare　Ti3N2　is　a　promising　anode　material　for　Li-ion　or　non-Li-ion　batteries.　©　2019　The　Royal　Society　of　Chemistry.