Rechargeable Zn batteries (ZBs) have received increasing attention due to their cheap, safe and green characteristics, but their further development is generally bottlenecked by lack of compatible electrolytes. Here we report an eco-friendly and low-cost amide-based molten salt (AMS) containing acetamide, lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) and trifluoromethylsulfonate (Zn(Tfo)2) for ZBs. This AMS electrolyte enables a ∼100% Zn plating/stripping efficiency with long-term stability and suppresses Zn dendrite growth. Based on the Li+ extraction/insertion on the cathodes and reversible Zn chemistry on the anode in this AMS electrolyte, both Zn/LiMn2O4 and Zn/LiFePO4 batteries show excellent electrochemical performance including large specific capacity (118 and 140 mAh g−1, respectively) and remarkable cycle life (>150 cycles). More importantly, by virtue of the electrochemical stability of the AMS, the voltage limit can be significantly increased above 2.15 V for the Zn/LiMn2O4 battery, making full use of the cathode capacity. This finding opens new opportunities for the development of low-cost and high performance ZBs.