Application Of Imidazolium Ionic Liquids EMIBF₄ And Pyrrole Ionic Liquids PY13FSI In Lithium Ion Battery

With the in-depth application of lithium ion battery in many industry, people has higher requirement on the properties of lithium ion batteries. Security problems become an important obstacle of the development of lithium ion batteries. For larger power battery, the security problem is more prominent, so the security problem is restricting the lithium ion battery to develop in the direction of large-scale, high energy.Graphiteas negative, with ionic liquid and 1 mol/L Li PF6/EC+DMC+DEC mixed electrolyte as electrolyte assemble half cell, cobalt acid lithium as anode, with ionic liquid and 1 mol/L Li PF6 /EC+DMC +DEC mixed electrolyte as electrolyte assemble half cell. Using constant current charge and discharge, cyclic voltammograms(CV)and electrochemical impedance spectroscopy(EIS) method such as electrochemical properties of electrode materials was studied, and the flammability test is adopted to the stability of the ionic liquid is studied. In the process of characterization of electrode materials, we mainly got the following conclusions:(1)The ionic liquid PY13 FSI adding slightly reduces the initial discharge specific capacity of graphite, but the cycle performance is very good; Adding PY13 FSI have no negative effects on charge and discharge capacity and charging and discharging efficiency of the battery.(2) In CV results, we can acquire that with the adding of PY13 FSI in 1 mol/L Li PF6/EC+DMC+DEC, it can inhibit the reductive decomposition of EC for graphite electrode for the first time in the process of charging and discharging, helps to form a more smooth and tight SEI film, thus improve the performance of the cycle of graphite anode.(3) In the original electrolyte Adding different volume content PY13 FSI, with the increase of the content, the combustion intensity is reduced, burning time shorten,combustion performance is reduced, the safety performance improved.(4) EMIBF4 addition have no greater impact on cobalt acid lithium first discharge specific capacity; with different content of EMIBF4 the charging and discharging capacity basically remain unchanged after 50 weeks, so the cycle performance is very good.(5) CV test results, we can observe: after add 10% EMIBF4, CV curve contact ratio has improved significantly, it shows that after adding 10% of Imidazolium ionicliquids, the cycle of the battery performance are improved significantly. Contrast CV result, we can know, 10% EMIBF4 is added in the electrolyte, Can significantly inhibit the reduction of EC decomposition in the process of the first charge and discharge, helps to form a more smooth and tight SEI film, thus improve the performance of the cycle of the battery.