Transition-metal　chalcogenides　(TMCs)　are　attractive　high-capacity　anode　candidates　for　secondary　batteries,　but　they　suffer　from　significant　challenges　including　dramatic　volume　expansion　and　rapid　capacity　fading.　Despite　considerable　progress,　it　was　still　a　big　challenge　to　achieve　hundreds　of　stable　cycles　with　high　capacity　retention.　Herein,　we　reveal　that　the　copper　(Cu)　current　collector　corrosion　due　to　the　sulphur　(S)　species　attack　leads　to　serious　decay　in　anode　performance　in　TMC-based　batteries,　as　evidenced　by　the　side-reaction　product　Cu2S　generated　via　the　consumption　of　S　and　Cu　on　the　cycled　TMC　electrode.　The　electrochemical　test　and　DFT　calculations　both　reveal　that　the　resultant　Cu2S　increases　the　resistance　at　interfaces　and　reduces　the　charge　transfer,　leading　to　a　low　capacity　and　short　lifespan.　By　simply　introducing　a　conductive　layer　between　Cu　foil　and　TMCs,　the　corrosive　influence　of　Cu　is　remarkably　suppressed,　resulting　in　much　enhanced　cycling　performance.　At　current　densities　of　0.5C　and　1C,　the　Cu/2hTi/MoS2　sample　delivered　a　high　discharge　capacity　of　1010　and　740　mA　h　g(-1)　after　400　cycles,　respectively.　This　work　provides　new　insights　to　understand　the　fundamental　mechanism　of　the　electrochemical　reactions　and　strategy　to　improve　the　energy　storage　ability　of　TMCs.