First-principles　calculations　were　employed　to　study　the　effects　of　the　addition　of　ZrO2　on　the　electrochemical　activity　and　structure　of　Ir–Zr　binary　oxide.　In　the　computation　model　employed,　Zr　atoms　replaced　Ir　atoms　in　IrO2　supercells,　so　as　to　form　a　rutile-type　solid　solution　of　Ir1−xZrxO2　(0　≤　x　≤　1).　IrO2–ZrO2　oxide　coatings　were　prepared　on　Ti　substrates　by　thermal　decomposition.　X-ray　diffraction　(XRD)　analyses,　cyclic　voltammetry,　and　galvanostatic　charge/discharge　tests　were　performed　to　investigate　the　effects　of　the　Zr　content　on　the　structure　and　capacitive　performance　of　the　synthesized　Ti/IrO2–ZrO2　electrodes.　As　the　Zr　content　was　increased,　the　density　of　state　of　Ir1−xZrxO2　moved　to　a　higher　energy　level,　and　a　forbidden　band　was　formed,　which　reduced　its　electronic　conductivity.　The　XRD　analyses　showed　that　ZrO2　restrained　the　crystallization　of　IrO2.　Thus,　the　extent　of　the　amorphous　phase　increased　with　the　increase　in　the　ZrO2　content,　indicating　that　the　proton　conductivity　of　the　binary　oxide　coating　increased　with　the　ZrO2　content.　When　the　ZrO2　content　was　higher　than　50　mol%,　the　IrO2–ZrO2　coating　exhibited　a　relatively　narrow　energy　band　gap　(0.42eV)　and　a　＇amorphous/crystalline＇　structure,　as　well　as　the　highest　charge　capability,　indicating　that　its　electronic　and　protonic　conductivities　had　reached　an　equilibrium.　This　was　in　accordance　with　the　sudden　variation　in　the　length　of　the　M-O　bond　and　the　change　in　the　bulk　modulus.　©　2016　The　American　Ceramic　Society