Application Of Ionic Liquids-based Three-phase Microemulsion In The Enzymatic Catalysis

Because of the high specific energe, no memory, light pollution of the environment, high workingvoltage, long cycle life and small self-discharge performance, lithium ion battery has been widely appliedin areas such as mobil phone, laptop, camera and electric cars. The specific energy of some high power LIBhas been reached120Wh/kg-1, and the cycle life has been over1000times. Now, the basically cathodematerial of lithium ion battery has LiMO2(LiCoO2, LiNiO2) system, lithium manganese oxide (Li-Mn-O)system, and lithium vanadium oxide (LiV3O8) system. The Li-Mn-O system, especially spinel LiMn2O4has3D tunnel structure which can make the insertion and abjection of Li+more easy than the the interlayercompounds system, and has many advantages such as easy preparation, low pollution, low-cost, resourcefuletc.However, as a green energy, the cycle life of the lithium ion batteries is generally in about threeyears. So, at the same time, the lithium ion batteries will become a main part of the solid waste which cannot be ignored. The recycling of LIB is partically important, because lithium ion secondary batteriescontain a number of refractory organic solvens and metal ions. For example, the LiPF6which belongs to thelithium ion batteries has stong corrosive. On the one hand, the LiPF6can react with water producing HF.On the other hand, it can rest with strong oxidizer with the product P2O5. And the mental ions such as coalt,nickel and copper which have a cumulative effect in the environment can endanger human itself throughthe food chain on the one hand. On the other hand, the mental ions are broad-spectrum and some are stillrare precious metals such as cobalt. As a resoult, the spent lithium ion batteries are greatly harmful.However, if we can recycle the spent LIB, it will not endanger the environment and at the same time, it hasa centain economic benefit.In this paper, we get the cathode materials samples from spent lithium ion batteries through acentain process. Then the solution conditions of the waste lithium ion battey cathode materials LiMn2O4incricic acid solution was studied by adopting the combination of single factor and orthogonal experimentmethod. At last, the new, available anode materials spinel LiMn2O4samples were prepared successfullythrough sol-gel method. We observed the crystal structure and morphology characteristics of manganese acid lithium anode material through X-ray diffractometer (XRD) and scanning electron microscope (SEM)technology.Through this research, the experiment conclution as follows:(1) the process of the recyclingfrom waste lithium ion batteries was as follows: spent lithium ionbatteriesâ†'dischargingâ†'dismantlingâ†'screeningâ†'breakingâ†'sintering1h under500℃â†'mixture samplesof LiMn2O4â†'sintering2h under800℃â†'pure recycling samples of LiMn2O4.(2) The optimum dissolutionconditions were the concentration of citric acid,1.0mol/L; the dissolution temperature,45℃; the addedcontent of H2O2,5.0%; the solid-liquid ratio,60g/L. And the dissolution ratio was99.56%under theoptimum solution conditions.(3) At last, the new, available anode materials spinel LiMn2O4samples wereprepared successfully through sol-gel method. It turned out that the optimum preparation conditions asfollows: presintering4h under350℃and sintering12h under700℃. The products prepared under theseconditions posses obvious spinel structure and the electrochemical characteristics of the products wereexcellemt. Its first discharge capacity have reached128mAh g-1.The innovation of this research as shown below: For the first time, we used citric acid as solventto dissolve waste lithium ion battery cathode materials LiMn2O4. At the same time, we prepared new spinelLiMn2O4samples successfully through sol-gel method. On the one hand, we discussed the influence ofdifferent dissolution conditions on the dissolving rate; On the other hand, the different calcinationconditions on the crystal structure and electrochemical performance of LiMn2O4materials were alsodiscussed.