鈉電池層狀正極-P2/O3混相之鈉銅鐵錳氧材料開發

P2/O3 Phase-Integrated Na-Cu-Fe-Mn Cathode Materials for Sodium-Ion Batteries

許惟筑(Wei-Chu Hsu)

指導教授 ： 劉偉仁

中原大學/工學院/化學工程學系/碩士(2024年)

https://doi.org/10.6840/cycu202400802

摘要

隨著技術的快速發展和近年來電動汽車行業的崛起，對能源儲存設備和市場需求不斷增加。在這一趨勢中，鈉離子電池的研究引起了廣泛關注，我們從中獲得了寶貴的研究經驗和發展技術。鈉離子電池具有成本低、資源豐富的優勢，不僅在能量密度和容量性能方面有所提升，還具有壽命長和充電時間縮短等特點。目前，鈉離子電池也廣泛應用於各種能源儲存設備中。
在本研究中，我們成功使用傳統固態高溫燒結技術製備了 Na-Cu-Fe-Mn-O 層狀金屬氧化物，為了探討 P2/O3 晶體結構，因此我們首先會先探討 Na 過量效應(Na: Mn= 0.7:1, 1;1, 1:0.7)，並以 900度 在空氣氣氛下進行燒結，後續發現當 Na:Mn比例為 0.7:1.0 的時候電性表現最佳，後續我們在此基礎上引入 Fe 取代部分 Mn並確定最佳組成為 Na0.7Fe0.2Mn0.8O2，但基於這兩者組成之 Fe、Mn 層狀氧化物在潮濕空氣中暴露時不穩定的化學性質，會導致層狀結構不穩定和容量衰減，為解決這些問題，我們使用 Cu 掺雜希望可提高 P2 型 Fe、Mn 基氧化物的能量密度與穩定性，從而提高了倍率性能，同時透過調整 Na 含量使結構成為 P2/O3 雙相結構，並使用了 X 射線衍射 (XRD)、能量色散 X 射線光譜 (EDX)、掃描電子顯微鏡 (SEM)、穿透射電子顯微鏡(HRTEM）以及充放電循環、倍率性能、交流 阻 抗 和 循 環 壽 命 等 電 化 學 測 試 來 研 究 材 料 的 電 性 能 ， 經過測試Na0.9Cu0.2Fe0.4Mn0.4O2為電性表現最佳樣品，首圈庫侖效率可以達 98 %，循環穩定性能大幅提升，經過 100 圈循環測試電容保留率約 78.10 %，這表明 Cu 的掺雜和 Na 含量的調整能顯著提高層狀氧化物的能量密度與穩定性，從而提高倍率性能。未來我們將專注於深入探索材料組成和製程工藝的優化，以期實現更高效能和長壽命的層狀金屬氧化物電極材料。

關鍵字

鈉離子電池 ； 正極材料 ； 銅摻雜 ； 鐵摻雜 ； P2/O3 結構

並列摘要

With the rapid development of technology and the recent rise of the electric vehicle industry, the demand and market requirements for energy storage devices have been continuously increasing. In this trend, research on sodium-ion batteries has widespread attention, from which we have gained valuable research experience and development techniques. Sodium-ion batteries possess the advantages of low cost and abundant resources. They have not only improved in energy density and capacity performance but also feature long lifespan and shortened charging time. Currently, sodium-ion batteries are also widely used in various energy storage devices.In this study, we successfully synthesized Na-Cu-Fe-Mn-O layered metal oxides using the traditional solid-state high-temperature sintering technique. To investigate the P2/O3 crystal structures, we first explored the effects of sodium excess (Na:Mn = 0.7:1, 1:1, 1:0.7) and sintered the samples at 900 ℃ in an air atmosphere. We found that the best electrochemical performance was achieved when the Na: Mn ratio was 0.7:1.0.
Next step, we introduced Fe to replace the ratio of Mn and get the optimal composition to be Na0.7Fe0.2Mn0.8O. However, the Fe and Mn layered oxides with this composition exhibited unstable chemical properties when exposed to humid air, leading to structural instability and capacity degradation. To address these issues, we doped “Cu” ions to improve the energy density and stability of the P2-type Fe and Mn-based oxides, thereby enhancing the rate performance. Additionally, we adjusted the Na content to achieve a P2/O3 biphasic structure. The analyses of the materials were used X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), as well as electrochemical tests including charge/discharge cycling, rate performance, AC impedance, and cycle life. The Na0.9Cu0.2Fe0.4Mn0.4O sample exhibited the best electrochemical performance, with significantly improved cycle stability. The initial Coulombic efficiency was about 98%, and after 100 cycles, the cycle stability was close
to 78.10 %, confirming that this is the success of this modification.

並列關鍵字

Cathode material ； Sodium battery ； Layered oxide ； P2/O3 structure

參考文獻

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