The　high-voltage　stability　of　electrolytes　profoundly　determines　electrochemical　reactions,　which　is　still　one　of　the　major　obstacles　for　developing　advanced　Al-ion　batteries　(AIBs).　Herein,　a　fluorine-adjustment　strategy　is　proposed　to　improve　the　high-voltage　stability　of　a　low-cost　AlCl3/acetamide　(AcA)　deep　eutectic　solvent　electrolyte.　By　using　a　fluorine-substituted　AcA　additive,　the　AlCl3/AcA　electrolyte　exhibits　a　lifted　oxidation　onset　potential　from　2.21　to　2.78　V　versus　Al3+/Al.　Based　on　a　series　of　structural　investigations,　it　is　found　that　the　additive　can　adjust　the　coordination　configurations　and　improve　the　anti-oxidation　capability　of　electrolytes.　Moreover,　the　additive　induces　an　F-rich　interphase　layer,　which　can　stabilize　the　plating/stripping　reactions　of　Al　electrode　with　accelerated　kinetics.　Based　on　the　optimized　electrolyte,　a　high-voltage　Al-S　battery　relying　on　the　S　cationic　redox　shows　good　performance　with　little　voltage　fading　for　300　cycles.　This　study　provides　important　insights　into　the　exploration　of　high-performance　and　low-cost　electrolytes　for　AIBs.