Copper　foil　roughness　is　widely　regarded　as　an　important　factor　affecting　the　performance　of　lithium-ion　batteries,　but　relevant　research　still　lacks　systematic　and　in-depth　analysis.　In　this　paper,　6 μm　copper　foil　is　prepared　by　electrodeposition　and　compared　with　purchased　6　μm　copper　foil.　The　influence　of　different　roughness　on　the　battery　performance　is　analyzed　by　the　distribution　of　relaxation　time　(DRT).　The　results　show　that　the　roughness　of　homemade　copper　foil　(1.69 μm)　is　slightly　higher　than　that　of　purchased　copper　foil　(1.53 μm).　The　initial　charging　specific　capacity　of　the　homemade　copper　foil　electrode　reaches　372.51 mAh g−1,　significantly　higher　than　that　of　the　purchased　copper　foil　electrode　(323.89 mAh g−1).　DRT　is　used　to　analyze　the　electrochemical　reaction　kinetics　of　the　batteries,　it　is　found　that　the　copper　foil　with　a　certain　roughness　can　enhance　its　binding　with　the　active　substance,　ensure　stable　and　rapid　conductive　contact,　reduce　the　side　reaction　caused　by　uneven　lithiation,　and　minimize　the　increase　in　the　impedance　of　each　part　during　the　electrode　cycle,　thereby　ensuring　stable　battery　operation.　This　study　provides　new　insights　into　the　application　of　copper　foil　in　batteries　and　verifies　the　feasibility　of　homemade　6 μm　copper　foil.　©　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature　2025.