The effects of Li salts on the performance of a polymer actuator based on single-walled carbon nanotube-ionic liquid gel

Abstract

The effects of Li salts (Lithium tetrafluoroborate (Li[BF4]) and Lithium bis(trifluoromethanesulfonyl)imide (Li[TFSI])) on the electrochemical and electromechanical properties of an actuator using a polymer-supported single-walled carbon nanotube (SWCNT)-ionic liquid (IL) gel electrode were investigated. The ionic conductivities of the gel electrolyte layers with molar ratios of Li[BF4]/1-ethlyl-3-methylimidazolium tetrafluoroborate (EMI[BF4]) = 0.1 and 0.5, and Li[TFSI]/1-ethlyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMI[TFSI]) = 0.1 and 0.3 were higher than those containing only EMI[BF4] and only EMI[TFSI], respectively. We found a large capacitance value 65–96 F/g at a slow sweep rate 1 mV s−1. The actuator containing Li salt/IL performed much better than that containing only IL. It is considered that the higher ionic conductivity of the gel electrolyte layer containing Li salt/IL produces the quick response actuator, and that the large capacitance gives a large generated strain.