Aqueous　zinc　ion　batteries　(AZIBs)　are　promising　candidates　for　large-scale　energy　storage　due　to　their　low　cost,　high　safety　and　environmental　sustainability.　However,　they　still　face　limitations　in　cycling　life,　caused　by　dendritic　Zn　growth　and　severe　interface　side　reactions.　Recent　research　indicates　that　water　dipoles　in　the　Helmholtz　plane　are　the　main　culprits　causing　these　side　reactions.　Herein,　we　synergistically　engineer　the　inner　Helmholtz　plane　and　outer　Helmholtz　plane　at　the　interface　by　a　multifunctional　ionic　liquid　with　self-buffering　pH　characteristics,　pyridine　trifluoroacetate　(PYTR),　obtaining　a　water-scarce　inner　Helmholtz　plane　and　TR-　involved　in　the　solvated　structure　during　the　cycling　process　can　rapidly　de-solvated　and　form　an　organic–inorganic　hybrid　SEI　layer　on　the　surface　of　the　zinc　anode.　The　hydrophobic　PY+　ions　can　stably　adsorb　onto　the　Zn　surface　and　participate　in　the　formation　of　inner　Helmholtz　plane,　forming　water-scarce　inner　Helmholtz　plane　and　effectively　preventing　side　reactions　caused　by　water　dipoles.　The　TR-　ions　participate　in　regulating　the　solvation　structure　of　hydrated　Zn2+,　forming　an　outer　Helmholtz　plane,　thus　facilitating　the　formation　of　ZnF2-rich　SEI　during　electrochemical　cycling　process.　As　a　result,　the　Zn|Cu　half　cells　can　cycle　stably　with　a　high　coulombic　efficiency　(CE)　of　∼　99.8　%　over　1500　cycles,　and　the　Zn‖Zn　symmetric　cells　can　maintain　1600　h　at　a　current　density　of　1.0　mA　cm−2,　due　to　the　construction　of　a　water-poor　Helmholtz　plane　as　well　as　a　stable　SEI　layer,　＞6700　h　of　cycling　at　0.2　mA　cm−2/0.2　mAh　cm−2　were　achieved.　Additionally,　Zn‖(NH4)2V6O16　full　cells　assembled　with　a　low　N/P　ratio　(3:1)　can　run　stably　over　800　cycles　at　a　current　density　of　1.0　A　g−1.　This　work　provides　a　valuable　guideline　for　designing　the　Helmholtz　plane　in　aqueous　Zinc　ion　batteries.　©　2025　Elsevier　B.V.