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標題: | 中孔洞二氧化矽薄膜在無陽極鋰金屬電池的應用 Application of Mesoporous Silica Thin Film in Anode-Free Lithium Metal Batteries |
作者: | Chang-An Lo 駱昶安 |
指導教授: | 牟中原(Chung-Yuan Mou) |
關鍵字: | 介孔二氧化矽材料,枝晶鋰生成,無陽極鋰金屬電池, mesoporous silica material,lithium dendrite formation,anode-free lithium metal batteries, |
出版年 : | 2020 |
學位: | 碩士 |
摘要: | 在過去的幾十年裡,人們越來越多地探索用具有更高理論容量的鋰金屬代替傳統的陽極材料石墨。事實上,儘管鋰金屬是下一代儲能系統中有前途的候選者,但鋰金屬陽極的應用卻受到循環過程中不可預測的鋰支晶的生成而內在挑戰的限制。表面不均勻的沉積會導致“死鋰”,這主要是由於剝離過程中電場不均勻所致。電鍍無基質鋰可簡化安全生產過程,並更好地控制樹枝狀結構。我們的策略是在商用集電器上通過垂直通道合成中孔洞二氧化矽薄膜(MSTF),以便在電池運行期間鋰離子通量更加均勻,同時,所產生均勻的沉積增強了鋰金屬的穩定性。這些垂直且有序的中孔洞孔通道具有明確的孔徑(〜6nm),可以為鋰離子在陽極和陰極之間提供均勻的通道,從而實現有效的電鍍/剝除鋰金屬。在電鍍/剝除鋰金屬的過程中,均勻的鋰離子分佈會使半電池中200圈的液體電解質中的庫侖效率(CE)高(> 99%)。為了獲得有關MSTF如何提高CE的更多關鍵資訊,我們使用SEM觀察了鋰金屬沉積的形貌。由於均勻的鋰離子通量,在使用MSTF集電器的初始循環中,鍍鋰的形貌相當平坦。此外,從GIWAXS研究了鋰金屬沉積,發現MSTF會使鍍上去的鋰金屬是ㄧ大塊的單晶。更重要的是,使用這種新型集電器開發無陽極的鋰金屬電池,MSTF集電器在第一圈的充放電中顯示出電鍍/剝離的可逆性,因此經過50圈的充放電後可以保持超過100 mAh / g的放電容量。 Replacing the traditional anode material, graphite, by Li metal with higher theoretical capacity has been increasingly explored over the last decades. Despite the fact lithium metal is a promising candidate for next generation energy-storage systems, the application of lithium metal anodes has been constrained by intrinsic challenges of unpredictable dendritic Li formation during cycling. Uneven surface deposition would cause “dead lithium” which is mainly due to the uneven electric field during stripping. Plating hostless Li results in easy and safe manufacturing, and better controls in dendritic structure is our purpose. Our strategy is to synthesize mesoporous silica thin film (MSTF) with perpendicular tunnels on commercial current collectors, so that Li cation flux will be more homogeneous during battery operation. At the same time, the resulting uniform deposition enhanced the stability of Li metal. These vertical and ordered mesoporous channels, which has well-defined pore diameter (~5nm), provide uniform pathways between anode and cathode for Li cation, leading to efficient Li plating/stripping. The homogeneous Li cation distribution during Li plating/stripping results in a high Coulombic efficiency (CE) ( >99%) in liquid electrolyte in a half-cell for 200 cycles. To obtain more critical information on how the MSTF enhances CE, we use SEM to observe the morphologies of Li deposition. The morphologies of Li plating at preliminary cycles are pretty flat with MSTF current collector due to homogenous Li cation flux. Moreover, crystalline of Li are studied from GIWAXS. Of greater consequence, use this novel current collector to develop anode-free Li metal batteries, and MSTF current collector shows dramatically reversibility of plating/stripping at 1st cycle so that it can retains more than 100 mAh/g of discharge capacity after 50th cycle. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/52064 |
DOI: | 10.6342/NTU202002639 |
全文授權: | 有償授權 |
顯示於系所單位: | 化學系 |
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