Aqueous lithium ion battery of nano-LiFePO4 with anti-freezing agent of ethyleneglycol for low temperature operation

Low-temperature performance of the rechargeable batteries is limited because of a narrow temperature range of the electrolyte. Despite the aqueous electrolyte has lower freezing point than the ethelyenecarbonate for conventional lithium ion batteries, its freezing point is as high as 0oC. Antifreeze additive of ethylene glycol for aqueous electrolyte solutions is used to improve the low-temperature performance of aqueous rechargeable lithium-ion batteries. The suitable contents of ethylene glycol expand the temperature range of aqueous electrolyte, persuing a balance between the low freezing point and high ionic conductivity and thus enhancing their cyclic performance, and decreasing the polarization of electrode reactions. Furthermore, the improvement of the lithium ion intercalation and deintercalation processes in the nano-LiFePO4 material at low temperature is controlled by varying the content of the antifreeze additive to provide a high ionic conductivity of an aqueous electrolyte solution having 1 M...