氟化石墨烯複合結構於鋰離子電池的人工固態電解質界面膜之研究;The study of artificial solid electrolyte interface by using the fluorinated graphene composite structure in lithium-ion battery

NCUIR > Engineering College > Energy of Mechatronics > Electronic Thesis & Dissertation > Item 987654321/88241

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/88241

Title:	氟化石墨烯複合結構於鋰離子電池的人工固態電解質界面膜之研究;The study of artificial solid electrolyte interface by using the fluorinated graphene composite structure in lithium-ion battery
Authors:	曾國豪;TSENG, KUO-HAO
Contributors:	能源工程研究所
Keywords:	鋰金屬電池;無黏著劑;人工固態電解質介面;氟化石墨烯;Lithium metal battery;Binder-free;Artificial solid electrolyte interface;Fluorinated graphene
Date:	2021-12-27
Issue Date:	2022-07-13 20:19:14 (UTC+8)
Publisher:	國立中央大學
Abstract:	在移動設備和電動汽車和各種應用中都需要大量能源的今天，高容量和穩定性的儲能設備，鋰離子電池 (LIBs) 在幾十年來引起了研究人員的關注。但商業使用的負極材料石墨的理論容量相對較低，LIBs 的能量密度從 1990 年代（80 Wh/kg）到現在（250 Wh/kg）並沒有太大提高。為了解決上述問題，進行了許多研究，發現直接電鍍鋰的理論容量更高（>3800 mAh/g），因此鋰金屬電池（LMBs）成為新一代儲能設備的解決方案。然而，LMBs的研究一直存在枝晶生長會消耗鋰或穿透隔離膜，導致LMBs性能下降甚至導致電池失效的問題。為了解決這個問題，一種人工固態電解質中間相（ASEI）的有效策略被用作保護層，以增強和穩定陽極性能。然而，儘管已經對合成ASEI進行了多項研究，但製備具有高機械強度且穩定的ASEI，並且容易控制的沉積方法仍然具有挑戰性。在這項研究中，通過使用電泳沉積法 (EPD) 沉積 FECG（氟化電化學剝離石墨烯）來製備新型 ASEI並研究其電化學特性。此外，在ASEI薄膜中添加了使用噴霧乾燥製作的FECG微米球，然後進行水熱氟化製程，通過提供結構支撐和石墨烯球所構成的LMBs的鋰離子傳輸隧道來增強機械強度和穩定性。本研究通過分析庫侖效率（CE）、過電壓電位、極化曲線等電化學測量，並觀察鋰沉積與脫附過程中ASEI結構的變化，並探討電池性能與ASEI厚度和結構之間的關聯性。本研究發現FECG片/球於2:1重量比的優化厚度為2μm。ASEI可以成功地提高穩定性並抑制LMBs中枝晶的生長。具有上述 ASEI 的 LMB 顯示出低成核過電位(57.3 mV)，400次循環後CE穩定性達87.63%，以及在半電池中長達400小時的優異之極化性能。此外，還證明了全電池LMBs（NCM-622）在50次循環後具有高容量(>120 mAh/g)。該研究通過混入FECG球作為結構支撐並藉此額外增加鋰傳輸隧道來提升LMB的效能，為功能性之新穎ASEI材料提供了一種新策略。 ;Upon the request of high capacity and stable energy storage devices for various applications such as mobile devices and electric vehicles, lithium-ion batteries (LIBs) had captured researcher attention in these decades. However, the energy density of LIBs had not improved much since the 1990 s (80 Wh/kg) to the present (250 Wh/kg) due to the limitation of the relatively low theoretical capacity of graphite, the commercially used anode material. According to the mentioned issue, lithium-metal batteries (LMBs) had seemed like the solution and the new generation of energy storage devices because of the higher theoretical capacity of directly plating lithium (>3800 mAh/g). However, the research of LMBs had been suffered from the dendrite grow which would consume the lithium or penetrate the separator which made the performance of LMBs decline or even lead to the failure of batteries. To address this issue, an effective strategy of deposing an artificial solid electrolyte interphase (ASEI) had been purposed to act as a protecting layer to enhance and stable the anode performance. However, although several efforts have been investigated to synthesis ASEI, a well-controlled deposition method preparing a stable ASEI with high mechanical strength is still challenging and not yet purposed. In this study, a novel ASEI was prepared by depositing a FECG (fluorinated electrochemically exfoliated graphene) layer with the electrophoretic deposition (EPD) method. Additionally, spray dry ECG balls followed by hydrothermal fluorination process were added in the ASEI film to enhance the mechanical strength and stability by providing structure supporting and extra lithium transport tunnels of LMBs. The effects between the batteries′ performance and both thickness and structure were investigated in this study by analyzing the electrochemical measurement such as coulomb effect (CE), overvoltage potential, polarization profile, and observing the change of the ASEI structure during the lithium stripping/plating. As a result, an optimized ASEI thickness of 2 μm with a FECG sheet/ball ratio of 2:1 (wt.) could successfully improve the stability and inhibit the growth of dendrite in LMBs. The LMBs with the mentioned ASEI showed a low nucleation overpotential (57.3 mV), high stability of CE up to 87.63% after 400 cycles, and a remarkable polarization performance for up to 400 hours in a half-cell. In addition, full-cell LMBs (NCM-622) with an excellent capacity for up to >120 mAh/g after 50 cycles was also demonstrated. This study provided a new strategy for improving the mechanical strength of ASEI by introducing FECG ball as a structure supporting and extra lithium transport tunnels realizing the potential of LMBs.
Appears in Collections:	[Energy of Mechatronics] Electronic Thesis & Dissertation

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