With　the　emergence　of　the　energy　crisis　and　the　rise　of　human　environmental　awareness,　lithium-ion　batteries　(LIBs),　as　a　new　type　of　energy　storage　device,　are　widely　used　in　electric　vehicles　(EVs),　mobile　electronic　products　and　stationary　energy　storage　devices.　The　demand　for　LIBs　has　dramatically　increased　in　recent　years,　leading　to　a　shortage　of　raw　materials　for　LIBs　and　a　large　number　of　retired　LIBs.　Therefore,　it　is　particularly　important　to　recycle　spent　LIBs.　Compared　with　pyrometallurgy　and　hydrometallurgy,　direct　recycling,　as　a　more　advanced　technology,　focuses　on　repairing　of　the　electrodes　of　spent　LIBs.　However,　direct　recycling　technology　is　still　in　the　laboratory　operation　stage,　and　there　are　still　many　difficulties　and　challenges　to　overcome.　Herein,　we　firstly　highlight　the　importance　of　recycling　spent　LIBs　from　LIB　market　development,　raw　material　supply,　environmental　impact,　and　economic　benefits.　Subsequently,　starting　from　the　failure　forms　and　mechanisms　of　electrode　materials,　we　provide　a　detailed　summary　of　various　direct　recycling　and　upcycling　processes,　reaction　principles,　as　well　as　advantages　and　disadvantages.　Additionally,　the　technology　for　converting　waste　cathodes　and　graphite　into　new　functional　materials,　a　topic　rarely　addressed　in　previous　reviews,　is　comprehensively　detailed　in　this　review.　Lastly,　we　provide　a　summary　of　the　current　status　of　LIB　recycling　and　present　future　challenges.　This　review　may　serve　as　a　source　of　inspiration　for　researchers　and　enterprises　to　develop　more　advanced　recycling　methodologies.　©　2024　Elsevier　B.V.