To　implement　the　growing　requirement　for　higher　energy　density　all-solid-state　lithium　batteries　(ASSLBs),　further　increasing　the　working　voltage　of　LiCoO2　(LCO)　is　a　key　to　breaking　through　the　bottleneck.　However,　LiCoO2　severe　structural　degradation　and　side　reactions　at　the　cathode　interface　obstruct　the　development　of　high-voltage　sulfide-based　ASSLBs　(＞=　4.5　V).　Herein,　a　nano-metric　Li1.175Nb0.645Ti0.4O3　(LNTO)　coated　LCO　cathode　where　microscopic　Ti　and　Nb　segregation　at　the　interface　during　cycling　potentially　stabilizes　the　cathode　lattice,　and　minimizes　side　reactions,　simultaneously,　is　designed.　Advanced　transmission　electron　microscopy　reveals　that　the　stable　spinel　phase　minimizes　the　micro　stress　at　the　cathode　interface,　avoids　structure　fragmentation,　and　hence　significantly　enhances　the　long-term　cyclic　stability　of　LNTO@LCO　@　4.5　V.　Moreover,　the　differential　phase　contrast　scanning　transmission　electron　microscopy　(DPC-STEM)　visualizes　the　nano-interlayer　LNTO　to　boost　Li+　migration　at　the　cathode　interface.　Electrochemical　impedance　spectroscopy　(EIS)　reveals　that　sulfide-based　cells　with　the　LNTO　nano-layer　effectively　reduce　the　interfacial　resistance　to　140　omega　compared　to　LiNbO3　(235　omega)　over　100　cycles.　Therefore,　4.5　V　sulfide-based　ASSLBs　offer　gratifying　long-cycle　stability　(0.5　C　for　1000　cycles,　88.6%),　better　specific　capacity,　and　rate　performance　(179.8　mAh　g(-1)　at　0.1　C,　97　mAh　g(-1)　at　2　C).