天然橡胶/丁苯橡胶基隔膜材料的制备与性能

采用相转换法制备出了以天然橡胶(NR)/丁苯橡胶(SBR)为基的多孔状聚合物锂离子电池隔膜材料,系统研究了成膜的工艺参数及机理.利用扫描电镜(SEM)和原子力显微镜(AFM)观察了该聚合物隔膜的微观结构,同时考察了该聚合物膜的吸液保液能力、热稳定性及电化学性能.结果表明,该聚合物膜呈多孔蜂窝状,具有较高的吸液能力,在电解液中浸泡5h后的吸液率达320%,此时该聚合物多孔隔膜的室温电导率也达到了3.93×10-4S/cm;并且保液能力良好,在50℃的空气中保持5h的质量损失仅为31%.同时该聚合物多孔膜具有较宽的电化学稳定窗口和较高的热分解温度,在4.8V和157℃以下能安全使用.与金属锂电极间的界面阻抗在存放10天或经过20次循环伏安扫描内迅速增加,而后趋于稳定,表现出了良好的界面稳定性,有效地抑制了电极与隔膜间的钝化膜(SEI)的进一步生长.

PREPARATION AND PERFORMANCE OF NATURAL RUBBER/STYRENE-BUTADIENE RUBBER BASED SEPARATORS

The natural rubber(NR)/stytene-butadiene rubber(SBR)based porous polymer membranes were prepared by means of phase-inversion,and the processing parameters and mechanism of membrane_forming were studied systematically.Microstructure of the porous membranes was observed using scanning electronic microscope(SEM)and atomic force microscope(AFM).Abilities of solution uptake and reservation,thermal stability and electrochemical performance were studied as well.Results show that the prepared polymer membranes are porous honeycombing with excellent solution uptake and reservation abilities,the solution uptake ratio is up to 320% and the mass loss is only 31% after heated at 50℃ for 5 h.With that solution uptake ratio,the conductivities arrive 3.93×10-4 S/cm at ambinet temperature.Electrochemical stability window(4.8 V)and thermal decomposition temperature(157℃)are suitable implying they can be used below 4.8 V and 157℃ safely.The interfacial impedance between membranes and lithium electrodes increase quickly after being kept for 10 days or scanned 20 cycles using cyclic voltammetry,and then,stabilized gradually,showing good interfacial stability which can surpress effectively further growth of solid electrolyte interface(SEI).