The　natural　abundance　of　potassium　in　the　earth＇s　crust　is　1000　times　higher　than　that　of　lithium,　so　energy　technologies　built　on　potassium　are　more　sustainable.　Potassium-ion　batteries　have　attracted　considerable　attention　because　of　their　relatively　low　cost　and　high　operating　potential,　but　questions　remain　about　the　best　anode　material　for　such　batteries.　Here,　we　report　first-principles　computations　based　on　density　functional　theory　to　investigate　the　performance　of　the　UiO-66　metal-　organic　framework　as　an　anode　material　for　potassium-ion　batteries;　the　goal　is　to　provide　a　fundamental　understanding　of　metal-organic　framework　(MOF)-based　electrodes　to　guide　the　design　and　development　of　high-performance　potassium-ion　batteries.　Our　study　includes　the　stability　and　electronic　properties　of　potassiated　structures　and　the　mechanisms　of　potassium　intercalation　and　diffusion　in　the　framework.　The　results　indicate　that　UiO-66　has　a　maximum　specific　capacity　of　644　mAh/g　as　the　anode　of　a　potassium-ion　battery.　During　potassiation,　we　observe　charge　transfer　from　potassium　to　carbon　or　oxygen　of　UiO-66　near　the　intercalated　K.　During　K　diffusion,　the　K　migrates　along　the　UiO-66　framework　with　a　maximal　migration　energy　barrier　of　0.377　eV　in　the　optimal　pathway,　which　is　much　lower　than　the　barriers　for　Li　and　Na　diffusion　in　UiO-66.　The　diffusion　coefficient　of　K　in　the　anode　is　several　orders　of　magnitude　larger　than　those　of　Li　and　Na.　This　favors　potassium　ions　over　lithium　ions　or　sodium　ions　when　UiO-66　is　the　anode.