Efficient　energy　recovery　from　electrochromic　(EC)　devices　gives　new　insight　into　reducing　the　consumption　of　energy　and　facilitating　the　recycling　of　energy.　However,　one　challenge　is　to　realize　the　effective　energy　storage　and　conversion　without　sacrificing　the　electrochromic　performance.　Herein,　spinel　Li4Ti5O12　(LTO),　a　desirable　anodic　material　for　lithium　ion　batteries,　was　employed　to　develop　a　rechargeable　electrochromic　energy　storage　device　(EESD),　instead　of　utilizing　conventional　capacitive　EC　materials.　Moreover,　the　LTO　film　exhibited　a　good　electrochromic　performance　in　terms　of　visible　and　near-infrared　transmittance　modulation　(54.9%　at　550　nm　and　71.6%　at　1000　nm),　indicating　that　it　can　effectively　block　90%　of　the　thermal　radiation　energy　in　the　sunlight.　In　addition　to　its　high　theoretical　capacity　and　excellent　structural　stability,　LTO　displayed　a　large　optical　contrast　during　energy　storage　and　conversion,　and　its　EC　mechanism　was　further　revealed　by　analyzing　its　electronic　structure　evolution　in　response　to　lithiation　based　on　density　functional　theory　calculations.　When　assembled　with　a　complementary　EC　NiO　anode,　the　well-designed　LTO-based　EESD　demonstrated　a　reversible　transmittance　variation　over　50%　between　charged　(colored)　and　discharged　(bleached)　states.　For　energy　storage,　the　rechargeable　EESD　with　a　high　operating　voltage　of　3.0　V　could　power　a　1.7　V　red　light-emitting　diode　(LED)　for　more　than　10　min　and　provide　an　energy　density　of　0.2　W　h　cm(-3),　which　is　superior　to　most　state-of-the-art　energy　storage　systems　based　on　conventional　EC　materials.　As　a　proof　of　concept,　EESD　is　designed　to　be　a　prototype　device　of　smart　window　to　elucidate　the　feasibility　for　energy　recovery　and　self-power　applications.　The　energy　used　to　drive　the　coloring　of　the　EESD　window　could　be　stored　on　a　sunny　day　and　then　power　a　household　lamp　(3　V/5　W)　at　night.　It　is　envisioned　that　the　rechargeable　EESD　in　this　work　will　provide　an　applicable　platform　for　effective　energy　recovery　in　real-world　applications　involving　advanced　energy　technology　and　smart　window　architecture.