关键词: 锂离子电池, 低温性能, 正极, 电解液, 负极

Abstract: Lithium-ion batteries (LIBs) have become a new research hotspot due to their high energy density and long service life. However, the temperature characteristics, especially the poor performance at low temperatures, have seriously limited their wider applications. In this report, the research progresses in the low temperature performance of LIBs are reviewed. The main existing limitations of LIBs at low temperatures were systematically analyzed, and followed by discussion on the recent improvements in low temperature performances by developing novel cathode, electrolyte, and anode materials. The developments for improving the low temperature performance of LIBs are prospected. The three most important factors that influence the low temperature electrochemical performance of LIBs are as follows: 1) a reduced ion conductivity of the electrolyte and solid electrolyte interface (SEI) film formed on the electrode/electrolyte interface; 2) increased charge-transfer resistances at both the cathode and anode electrolyte- electrode interfaces; 3) slow lithium diffusion in the electrodes. The above three points lead to high polarization and lithium deposition, which may cause problems in terms of performance, reliability and safety of the cell. The key point is to provide expedite paths for the transport of lithium ions and electrons at low temperatures. All the influential aspects, such as cathode, electrolyte,and anode, should be considered to improve the low temperature performance of LIBs. The low temperature electrolyte can be obtained by adjusting the relative compositions, and species of the solvent, salt, and additive. The conductivity of electrolyte can be improved by adding low melting point cosolvents and salts. In addition, use of electrolyte additives forming low impedance interface film is one of the most economic and effective methods to improve the low temperature performance. And the structure of electrode materials can be optimized by doping, coating and decreasing the particle size, which can ensure sufficient conductivity and shorten diffusion path length for lithium ions and electrons. Managing the electrolyte and developing electrodes are efficient methods to improve the low temperature performance. Future studies should be focused on achieving high performance lithium-ion battery materials.

Key words: lithium ion batteries, low temperature performance, anode, electrolyte, cathode