| 摘要: | 傳統鋰電池的製備常使用Poly(vinylidene difluoride) (PVDF)當作黏著劑以固定活性材料與導電物質。並以N-Methyl-2-pyrrolidone (NMP)做為溶劑，與活性物質及導電粒子混和，將漿料塗佈於鋁片上。含NMP的極板在烘箱經過長時間(10-24小時)高溫烘烤，去除溶劑以完成成極片。由於NMP有毒，所以回收過程必須有額外的溶劑回收系統，並且需要大量的烘烤設備，以及烘烤過程中需消耗大量的電力、時間成本，不符合環境友善及節能減碳的環保概念。
因此也有越來越多人朝著綠色環保這方面去改善鋰電池的製作過程，像是水性黏著劑黏著劑的開發，以減少現有溶劑NMP的使用，但使用水性黏著劑還是有遇到幾個問題像是去除水分的烘乾過程過長以及電容量、壽命低下等問題。
有鑑於此，本論文主要是使用光聚合高分子、熱聚合高分子取代傳統的電極黏著劑(PVDF)以解決傳統鋰電池，極片烘乾時間過長、使用有毒溶劑、耗時耗能的問題。
首先黏著劑方面，分成光聚合黏著劑以及熱聚合黏著劑。光聚合黏著劑將DE單體與G3E單體進行光聚合反應、熱聚合反應則是將DP單體與G3E單體進行熱聚合反應。組成Li[Ni1/3Mn1/3Co1/3]O2/Li半電池測試，利用電子掃描顯微鏡(SEM)、X-射線光電子光譜(XPS)、循環伏安法(CV)及電化學阻抗頻譜(EIS)進行探討。實驗數據證實此兩款黏著劑確實參與SEI的形成且能夠減少電解液以及鋰鹽的消耗還有分解，我們認為此兩款黏著劑可以緊密包覆電極，避免正極持續與電解液反應，讓電池能夠長圈數循環後仍能繼續維持良好的電量。光聚合黏著劑、熱聚合黏著劑，與傳統黏著劑相比，電池電容量在經過100圈充放電後，分別是、104.6(mAh/g)、120.1(mAh/g)、107.9(mAh/g)，電容保持率分別是76.6%、81.9%、64.3%，光聚合以及熱聚合黏著劑在電容量、高倍率充放電、壽命的表現都優於傳統鋰電池。
;In the preparation of traditional lithium batteries, Poly (vinylidene difluoride) (PVDF) is often used as binder to fix active materials and conductive substances. And N-Methyl-2-pyrrolidone (NMP) is used as a solvent, mixed with active material and conductive particles, and the slurry is coated on the aluminum foil. The battery plate that containing NMP is baked at high temperature for a long time (10-24 hours) in an oven to remove solvent. However, NMP is toxic, the recycling process must have an additional solvent recovery system, and a large number of baking equipment is required, and the baking process consumes a lot of electricity and time costs, which does not correspond to the environmental protection concept of environmental friendliness and energy saving and carbon reduction.
In view of this, this thesis mainly uses photo-curing polymer and thermal-curing polymer to replace the traditional electrode binder (PVDF) to solve the problem of traditional lithium battery manufacturing.
First of all, in terms of adhesives, it is divided into photo-curing binder and thermal-curing binder. In the photo-curing binder, the DE monomer and the G3E monomer are subjected to photopolymerization reaction. In the thermal-curing binder, the DP monomer and the G3E monomer are subjected to thermalpolymerization reaction. Composition Li[Ni1/3Mn1/3Co1/3]O2/Li half-cell test using scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) discuss. The experimental data confirm that the two binders are indeed involved in the formation of SEI and can reduce the consumption and decomposition of electrolyte and lithium salts. Compared with traditional binder, photopolymerized binder and thermally polymerized binder have a battery capacity of 104.6(mAh/g), 120.1(mAh/g), 107.9(mAh/g) after 100 cycles of charge and discharge, respectively. ), the capacitance retention is 76.6%, 81.9%, 64.3%, photopolymerized and thermally polymerized binder have enough performance to match or even surpass traditional lithium batteries.
Finally, we also used XPS, CV, and EIS to confirm that these two binder can tightly coat the electrodes to prevent the positive electrode from continuously reacting with the electrolyte, so that the battery can continue to maintain a good power after a long cycle. |
