The　state-of-the-art　layered　oxide　as　the　cathode　material　for　lithium-ion　batteries　has　attracted　wide　attention;　however,　harsh　operations　of　high-energy　and　high-safety　energy-storage　technology　at　high　temperature　is　challenging　owing　to　the　aggravated　structural　instability　and　parasitic　reactions　at　the　cathodes.　Herein,　the　layered/olivine　composite　structure　architecture　is　designed　at　the　grain　surface　to　govern　constant　electrochemistry　in　a　harsh　environment,　and　a　gradient　LiF　interlayer　is　developed　onto　the　cathodes　to　suppress　the　interfacial　degradation.　By　a　combination　of　interfacial-sensitive　characterizations　and　theoretical　analysis　at　the　cathode/interface,　the　formation　mechanism　of　this　special　interphase　induced　by　the　composite　structure　cathode　is　revealed.　The　composite　structure　cathode　could　deliver　an　excellent　high-temperature　cycling　stability　with　90.8%　retention　for　300　cycles　in　the　half　cell　and　95.6%　retention　for　1000　cycles　in　the　pouch　cell　and　simultaneously　enhances　similar　to　51%　of　the　thermal　stability,　which　broadens　the　approaches　for　developing　high-stable　cathodes　that　work　in　extreme　environments.