Electrochemical Characteristics of Cubic ZnFe ₂ O ₄ Anode for Li-Ion Batteries at Low Temperature 2016-01-1215

The poor low-temperature behavior of Li-ion batteries has limited its application in the field of electric vehicles and hybrid electric vehicles. Many previous studies concentrate on developing new type of electrolyte to solve this problem. However, according to recent research, the key limitation at low temperature is the low diffusivity of lithium ion in the anode electrodes. Hence, it is potential to study anode materials to improve low-temperature behavior of LIBs. ZnFe₂O₄ with higher theoretical capacity is low toxicity and abundance, contributing to its commercial application. Different ZnFe₂O₄ crystalline shapes have different particle sizes. Among them, the cubic ZnFe₂O₄ with smaller particle size will increase its own electronic and ionic conductance at lower temperature. In this regard, we evaluated low-temperature performance of LIBs with ZnFe₂O₄ cubes as anode materials at -25°C. The morphology, discharge/charge capacity, cyclic stability and electrochemical impedance of the electrode were investigated. It is found that the electrochemical behavior of ZnFe₂O₄ cubes at lower temperature is poor than that at ambient temperature, but is much better than that of commercial graphite. After the first low-temperature cycle, the reversible capacity of cubic ZnFe₂O₄ is still high to 422.2 mAh g^-1 and its retention rate of the initial capacity can reach about 44.64%. And, the ZnFe₂O₄ cubes can keep normal charging and discharging even after 100 cycles at -25°C, which can reduce the security hazard caused by the difficulty of Li-ion intercalation. These findings in our research have certain reference value for the development of LIBs applied at lower temperature.