【摘要】：LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正極材料由于其較高的可逆容量、穩(wěn)定的結(jié)構(gòu)、較強的熱穩(wěn)定性和相對較低的成本,已經(jīng)被很多研究人員進行了深入廣泛的研究。然而,研究人員對過渡金屬氧化物電極材料進行了更徹底的研究,發(fā)現(xiàn)經(jīng)過多次的充放電后其循環(huán)穩(wěn)定性能逐漸變差。此外,LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2鋰電池的快速容量衰減和低速率能力也是阻礙其在高功率應用中可持續(xù)性和使用性的主要問題。在本論文中,我們首先討論兩種過渡金屬摻雜的電極材料和它們的電化學性能。LiNi_(1/3)Cu_xCo_(1/3-x_Mn_(1/3)O_2和LiFe_xNi_(1/3-x)Co_(1/3)Mn_(1/3)O_2(0.000≤x≤0.267)兩種微球材料分別按化學計量利用銅摻雜替代鈷和鐵替代摻雜鎳進行合成。由于在銅摻雜材料中出現(xiàn)了顆粒的團聚和產(chǎn)生了雜質(zhì)相,導致比容量的降低。適量的鐵摻雜材料可以提高鋰離子電池的比容量。以MnO2微球為模板,用Zn摻雜三元系LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2材料,合成LiNi_(1/3)Zn_xCo_(1/3-x)Mn_(1/3)O_2(0.000≤x≤0.133)微球材料。一個空心微球顆粒的直徑大約為4微米,它又有大量300納米的小微粒組成。利用RIETAN-FP軟件對樣品進行XRD結(jié)構(gòu)解析,得出樣品具有α-NaFeO_2層狀結(jié)構(gòu)。然后組成鋰離子紐扣電池,在2.5V到4.5 V的電壓范圍內(nèi)進行電化學性能測試。通過測試,發(fā)現(xiàn)隨著鋅摻雜濃度的增加,鋰電池的循環(huán)性能和倍率性能同材料的晶格參數(shù)具有相似的變化趨勢。摻雜量x=0.133的樣品比其它樣品具有更好的電化學性能,與沒摻雜鋅的材料比較,其鋰電池比容量增加了10.7%。此外,LiNi_(1/3)Zn_xCo_(1/3-x)Mn_(1/3)O_2(x=0.133)空心微球材料的松散、多孔結(jié)構(gòu)有利于鋰離子在電極材料內(nèi)的遷移,并且可以儲存電解液,進一步增強鋰離子的擴散和電荷轉(zhuǎn)移。
[Abstract]:LiNi_ (1 / 3) Co_ (1 / 3) Mn_ (1 / 3) O _ 2 cathode material, due to its high reversible capacity, stable structure, strong thermal stability and relatively low cost, It has been extensively studied by many researchers. However, the researchers conducted a more thorough study of transition metal oxide electrode materials, and found that the cyclic stability of transition metal oxide electrode materials became worse after repeated charge and discharge. In addition, the rapid capacity attenuation and low rate capability of LiNi_ (1 / 3) Co_ (1 / 3) Mn_ (1 / 3) O _ 2 lithium battery are also the main problems that hinder its sustainability and usability in high-power applications. In this paper, We first discuss two transition metal-doped electrode materials and their electrochemical properties. LiNi_ (1 / 3) Cu_xCo_ (1 / 3-xMn_ (1 / 3) O _ 2 and LiFe_xNi_ (1 / 3-x) Co) Two kinds of Mn_ (1 / 3) O _ 2 (0.000 鈮，

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