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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71640


    Title: 氫化二氧化鈦作為鋰、鈉、鎂鋰雙離子電池電極活性材料之電化學性質研究;Hydrogenated TiO2 for Li-, Na-, and Mg/Li-ion battery electrodes
    Authors: 吳澍齊;Wu,Shu-Chi
    Contributors: 材料科學與工程研究所
    Keywords: 氫處理;二氧化鈦;鋰離子電池;鈉離子電池;鎂離子電池;雙鹽系統;hydrogenation;titanium oxide;lithium ion batteries;sodium ion batteries;magnesium ion batteries;dual ion system
    Date: 2016-08-31
    Issue Date: 2016-10-13 13:24:15 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 本研究將三種二氧化鈦晶相,anatase、bronzer及rutile氫處理成氫化二氧化鈦,並應用於鋰離子、鈉離子與鎂鋰雙離子電池,藉由氫化增進電極的導電度與電化學動力學性質,以提升電池性能。過往研究僅有將氫化應用於鋰離子電池,尚未有文獻報導應用於鈉離子與鎂鋰雙離子電池。
    實驗結果發現氫化anatase較原材在鋰離子、鈉離子與鎂鋰雙離子電池效能皆大幅提升。在鋰離子電池方面,在16.8 mA/g (0.05 C) 低電流密度下可得264 mAh/g;在10 A/g (30 C) 高電流密度下仍有34 mAh/g,經500圈循環壽命測試維持率仍有74%。鈉離子電池方面,在大電流充放電下10 A/g 仍可維持達94 mAh/g,在循環壽命上也有非常優異表現,以500 mA/g 測試4300圈循環壽命維持率,其電容值仍有110 mAh/g。在鎂鋰雙離子電池方面,在8.4 mA/g (0.05 C) 低電流密度下可得240 mAh/g;而在1680 mA/g (10 C) 高電流密度下仍可得95 mAh/g,而在168 mA/g (1 C) 循環壽命測試下,200圈循環壽命維持率達83%。
    效能提升原因可歸因於氫化後產生氧空缺,無序表面及Ti3+離子,氧空缺能提升材料導電性降低阻抗,無序表面能提供更多電化學反應活化點,而無序表面與Ti3+離子這兩者效應結合在氫化二氧化鈦表面產生擬電容儲存離子反應,能增進電化學動力學性質,提升其高速性能。然而bronze與rutile氫化後,僅在鈉離子電池上性能有所提升,鋰離子與鎂鋰雙離子電池則性能增益有限,推測可能與bronze氫化後產生相變,而rutile則是本身尺寸較大造成表面積少,因此氫化提升效能效益並不明顯。
    結果顯示氫化處理不僅對於鋰離子電池有效,對於鈉離子及鎂鋰雙離子電池效能也能大幅提升。但仍需考量材料是否會產生相變及尺寸效應問題。希望此技術未來能拓展至其他種類金屬氧化物電極於鋰、鈉、鎂和鋁離子等二次金屬離子電池等應用。;Hydrogenated transition metal oxides (TMOs) prepared via a hydrogenation treatment process have attracted increasing attention as electrodes in lithium ion batteries and supercapacitors, which is attributed to the improved electronic conductivity and electrochemical reactions kinetics. In this work, three different TiO2 phases including anatase (TiO2-A), bronze (TiO2-B), and rutile (TiO2-R) and their hydrogenated products (denoted with a prefix “H”) are investigated as electrodes in Li-, Na-, and Mg/Li-ion battery. We demonstrate, for the first time, the effects of hydrogenation treatment on electrochemical performances of TiO2 in Na- and Mg/Li-ion battery.
    Our experimental results shows that hydrogenation treatment improves the capacity of anatase TiO2 in MLIBs up to 240 mAh/g (at 8.4 mA/g), which is 2 times higher than the raw TiO2. Furthermore, the high rate capabilities of anatase TiO2 (HTiO2-A) in LIBs (34 mAh/g at 10A/g), NIBs (94 mAh/g at 10A/g), and MLIBs (95 mAh/g at 1.68A/g) are enhanced as compared to the raw TiO2-A. Regarding the cycle stabilities of HTiO2-A, 74% capacity is retained after 500 cycles for LIBs, while 60% after 4300 cycles for NIBs and 83% after 200 cycles for MLIBs. All these results indicate the significant benefits of hydrogenation treatment on the anatase TiO2.
    The enhanced performances might be explained by oxygen vacancies, disordered surface and Ti3+ ions created by hydrogenation process. The introduction of oxygen vacancies improves the electronic conductivity of materials, while the disordered surface may provide more active sites for electrochemical reactions. The combined effects of the disordered surface and Ti3+ induce pseudocapacitive lithium storage on the HTiO2 surface, which features much faster kinetics. However, hydrogenation treatment improves the electrochemical performances of the bronze and rutile phases only for NIBs, which is possibly attributed to phase transformation of the bronze phase and the larger particle size of the rutile phase.
    Conclusively, hydrogenation treatment enhances electrochemical performances of transition metal oxides not only in LIBs but also in SIBs and MLIBs although the simultaneous phase transformation and particle size are needed to be concerned. In the future, the developed hydrogenation technique potentially extends to a variety of metal oxide electrodes in lithium, sodium, magnesium, and aluminum ion battery applications.
    The experimental results show that the enhanced effect of hydrogenated treatment on transition metal oxides not only in lithium ion batteries but also in sodium ion battery and magnesium-lithium ion battery. Therefore, the developed hydrogenation technique potentially extends to a variety of metal oxide electrodes in lithium, sodium, magnesium, and aluminum ion battery applications.
    Appears in Collections:[材料科學與工程研究所 ] 博碩士論文

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