本研究中，利用高能量機械球磨法，以370 rpm持續12小時，合成Na3PS4、Na3SbS4、Na9SbP2S12和Na9SbP2S11Se硫屬化合物，再單軸加壓(469 MPa)製成碇狀，加熱至200°C，可令高能研磨粉末反應進行更完全。使用交流阻抗分析(AC impedance)、恆電壓測量與循環伏安法(Cyclic voltammetry)，測量對稱及非對稱電池構型之電化學性質。
將高能量球磨法合成過後之Na3PS4、Na3SbS4、Na9SbP2S12和Na9SbP2S11Se硫屬化合物粉末，加熱至200°C持續2小時，以X光繞射(X-ray diffraction)進行鑑定，在兩倍角(2θ)為15~50°出現數個很寬的背景繞射。X光繞射圖譜顯示Na3PS4和Na3SbS4立方相晶體繞射特徵。Na9SbP2S12和Na9SbP2S11Se繞射峰類似，應該是前兩種硫屬化合物具有同樣晶體結構的固溶體(solid solution)，另搭配元素組成比例進行確認。
比較利用不同策略提升鈉離子導電率的四種固態電解質，cubic Na3PS4硫屬化合物在降溫條件量測，得室溫之離子導電率為1.17 x 10-4 S cm-1。cubic Na3SbS4硫屬化合物在降溫條件量測，得室溫之離子導電率為2.93 x 10-4 S cm-1。Na9SbP2S12硫屬化合物在降溫條件量測，得室溫之離子導電率為3.66 x 10-4 S cm-1。Na9SbP2S11Se硫屬化合物在降溫條件量測，得室溫之離子導電率為4.40 x 10-4 S cm-1，Na9SbP2S11Se硫屬化合物為四種固態電解質中具有最高之室溫離子導電率，但彼此差距有限，同時在溫度110°C以上時，Na9SbP2S12硫屬化合物之離子導電率為四種中最高值。
Na9SbP2S12硫屬化合物其電子或電洞導電率(σe+h)為1.303 x 10-11 S cm-1，具有低電子導體特性，以Na9SbP2S12作為電解質將不會有漏電問題，Na9SbP2S12提供的電化學窗口達5.0 V (vs. Na/Na+)。
以循環伏安法觀察鈉金屬與Na9SbP2S12硫屬化合物之間的電化學反應，掃瞄範圍為-1.0 ~ 5.0 V (vs. Na/Na+)，結果顯示僅為單純鈉離子的還原反應與鈉金屬原子氧化反應，並無發現第三相反應產生。

In this study, Na3PS4, Na3SbS4, Na9SbP2S12 and Na9SbP2S11Se chalcogenide are synthesized by high energy mechanical ball-milling at 370 rpm for 12 h, and then the ball milled powder was compacted with uniaxial cold press (469 MPa) into a pellet. The pellet undergoes solid state reaction and crystallization through the heating procedure up to 200°C. The electrochemical properties of these sulfides are measured in symmetric and asymmetric cell configurations using AC impedance, constant voltage measurement, and cyclic voltammetry.
The ball milled Na3PS4, Na3SbS4, Na9SbP2S12 and Na9SbP2S11Se chalcogenide powders were heated to 200°C for 2 h. The X-ray diffraction patterns of Na3PS4, Na3SbS4, Na9SbP2S12 and Na9SbP2S11Se chalcogenide show a few wide background diffractions between 15° to 50° (2θ). The X-ray diffraction patterns of Na3PS4 and Na3SbS4 show somewhat shifted diffraction lines of the cubic phase. The Na9SbP2S12 and Na9SbP2S11Se diffraction peaks are similar, we think they are solid solutions of the parent structure. The sulfide compositions are confirmed with energy dispersive spectrometer (EDS).
The ion conductivity of cubic Na3PS4 chalcogenide is measured 1.17 x 10-4 S cm-1 at room temperature in the cooling ramp. The ion conductivity of cubic Na3SbS4 chalcogenide is measured 2.93 x 10-4 S cm-1 at room temperature in the cooling ramp. The ion conductivity of Na9SbP2S12 chalcogenide is measured 3.66 x 10-4 S cm-1 at room temperature in the cooling ramp. The ion conductivity of Na9SbP2S11Se chalcogenide is measured 4.40 x 10-4 S cm-1 at room temperature in the cooling ramp. The Na9SbP2S11Se chalcogenide is the highest ionic conductivity at room temperature, but it only slightly increased. At temperatures above 110°C, the Na9SbP2S12 chalcogenide is the highest ionic conductivity at room temperature. Thus we conclude that solid solutions do raise the ion conductivity of sodium chalcogenides.
Specifically, the electron/hole conductivity of the Na9SbP2S12 chalcogenide is 1.303 x 10-11 S cm-1 S cm-1 is estimated beyond 5.0 V (vs. Na/Na+), while the sodium ion conduction predominates within 0 – 5.0 V (vs. Na/Na+). Since the electron/hole conductivity is well less than the ion conductivity, Na9SbP2S12 as an electrolyte is not supposed to have leakage problem. Na9SbP2S12 chalcogenide had a wide electrochemical window up to 5.0 V (vs. Na/Na+).
The potentials are scanned from −1 to 5.0 V (vs. Na/Na+). We have found only the sodium ion reduction reaction and sodium metal atomic oxidation reaction, no third phase reaction. The results of cyclic voltammetry indicate that the window 0 – 5.0 V (vs. Na/Na+) can be used for the Na9SbP2S12 electrolyte.

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