以磁性離子摻雜之磷酸釩鋰與磷酸釩鈉之電池性能提升研究

Enhanced performance of superionic Li3V2(PO4)3 and Na3V2(PO4)3 batteries by insertion of magnetic ions

高振瑋(Cheng-Wei Kao)

指導教授 ： 楊仲準

中原大學/理學院/物理研究所/博士(2022年)

https://doi.org/10.6840/cycu202200046

摘要

本研究利用檸檬酸表面活性成功合成Li3V2(PO4)3與Na3V2(PO4)3，外表由碳層包覆，並且將5%與10%比例之磁性原子(Mn、Fe、Co、Ni)摻雜至樣品中。10%樣品在XRD實驗中發現有雜質，5%則皆為純相，當中皆無碳的峰值，代表碳為無序，由摻雜後晶格變化與吸收光譜實驗證實摻雜元素確實取代樣品中V之位置並且得知其價數。實驗主要以摻雜5%比例磁性原子之樣品與對照組比較彼此間的物性與電池性能關係。臨場變溫拉曼光譜實驗觀察外層無序的碳，分析D-band、G-band變化與強度比，得知碳層有序程度與V鍵結價數有關。
分別研究樣品在低電壓(銅極片)鋰/鈉離子嵌入能力與高電壓(鋁極片)鋰/鈉離子析出能力。測量變場50 cycle、c-rate實驗以觀察電容量穩定度與快速充放電的衰退度，所有樣品在快速至慢速充放電中皆有良好的回復性。在電池組抗分析趨勢中觀察Rct與V鍵結價數相關，且樣品表面因V鍵結價數影響碳層的電子，與碳層有序度導致表面的電荷轉移能力產生變化。離子擴散速度則與樣品晶格體積互相有些微之影響。在能量功率密度圖中發現，無論是LVP或是NVP，Fe離子是不錯的摻雜選擇。

關鍵字

電池

並列摘要

In this study, Li3V2(PO4)3 and Na3V2(PO4)3 were successfully synthesized using the surface activated method of citric acid. The surface is covered by a carbon layer and doped with 5% and 10% magnetic atoms (Mn, Fe, Co, Ni). XRD experiments showed that impurities were found in 10%-doped samples but not in the 5% ones. No carbon signal was found in XFD experiments, which means the carbon formed disordered. The variation of lattice constants and the X-ray absorption spectra experiments confirmed that the doped elements have partially substituted the vanadium in the samples. This study mainly compares the relationship between the physical properties of the sample doped with 5% magnetic atoms and the pure ones in the battery performance. Varied magnetic fields and temperatures Raman spectra experiments displayed the disordered carbon at the outer layer. The changes of D-band, G-band, and their intensities ratio referred to the order of the carbon layer and correlated with the bond valence of vanadium.
Study the intercalation/deintercalation behaviors of lithium/sodium ions under low voltage (for copper case) and high voltage (for aluminum case). The varied magnetic field, 50 cycles, and C-rate experiments checked conductor stability and charge-discharge decay. In the C-rate experiment, all samples have good response and recovery during difference/charging rate. The electrochemical impedance spectroscopy experiment shows that Rct is related to V bond valence. The electrons of the carbon layer are affected by the V bond valence on the surface of the sample, and crystallization of the carbon layer lead to changes in Rct. The ion diffusion rate and the sample lattice volume slightly influence each other. The energy to power density plot indicates that Fe ions are good doping options for LVP and NVP cases.

並列關鍵字

Battery

參考文獻

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