We designed a novel aqueous rechargeable lithium battery with LiFePO4/C (LFP) and LiMn2O4/C (LMO) as the anode and cathode, respectively; then investigated the battery in Li2SO4 aqueous electrolyte. We also studied the electrochemical behavior of LFP in aqueous electrolyte using cyclic voltammetry (CV). The material exhibited excellent electrochemical performance in the aqueous electrolyte, including good oxidation/reduction reversibility and cycling stability; almost no decays were observable after 200CV cycles. The diffusion coefficients of Li ions through the interface between the liquid electrolyte and the solid LiFePO4 in terms of intercalation and deintercalation were 1.22×10−14 and 9.97×10−15 cm2/s, respectively. The material could be completely intercalated/deintercalated with Li ions in the aqueous electrolyte, indicating the excellent performance of LFP in an aqueous solution. Further, an aqueous rechargeable lithium battery (ARLB), which we fabricated using LFP as the anode and LMO as the cathode, also exhibited quite good performance in aqueous Li2SO4 solution: after 1,000 charge–discharge cycles at 2C, the capacity loss was less than 30%, indicating that this type of ARLB has excellent cycling stability and may be promising for future research and application.