The　uncontrollable　dendrite　growth,　hydrogen　evolution,　and　other　side-reactions,　originating　from　the　zinc　anode,　have　severely　restricted　the　practical　application　of　aqueous　zinc–ion　batteries　(ZIBs).　To　address　these　challenges,　a　stable　solid-electrolyte-interface　(SEI)　layer　is　constructed　through　introducing　sericin　molecules　as　an　electrolyte　additive　to　modulate　the　Zn　nucleation　and　overpotential　of　hydrogen　evolution.　This　SEI　layer　increases　the　nucleation　overpotential　during　Zn　plating,　leading　to　the　finer-grained,　dense,　and　uniform　Zn　deposition.　Meanwhile,　the　lower　unoccupied　molecular　orbital　molecules　in　SEI　layer　have　a　higher　reduction　potential　than　H2O,　inhibiting　hydrogen　production,　and　subsequently　suppressing　the　Zn　dendritic　and　interfacial　side-reactions.　Consequently,　the　Zn|Zn　symmetric　cells　with　sericin　additives　exhibit　an　extremely　prolonged　cycling　lifetime　of　4446 h　compared　with　to　bare　Zn　electrode　of　53 h　at　1.0 mA cm−2/1.0 mAh cm−2,　and　a　high　average　Coulombic　efficiency of　99.29%　under　a　high　cumulative　plated　capacity　of　1.0 Ah cm−2　tested　in　Zn|Cu　cells.　Moreover,　the　assembled　full　cells　using　Na2V6O16·3H2O　cathodes　endure　2000　cycles　with　high　capacity　retention　of　81.7%　at　5.0 A g−1.　This　study　sheds　new　light　on　modulating　the　process　of　Zn　nucleation　and　overpotential　of　H2　evolution　for　durable　Zn　anode　design.　©　2022　Wiley-VCH　GmbH.