石榴石型鋰離子導體於鋰離子電池之應用

本研究生產摻雜鋁之鋰鑭鋯氧固態電解質(lithium lanthanum zirconium oxide; Li7La3Zr2O12; LLZO)，無摻雜諸如鉭之高成本元素，並以X光繞射(X-ray diffraction)測定晶相，確認成功合成立方鋰鑭鋯氧固態電解質，再藉伏安循環法提高其離子傳導性，並與無伏安循環之樣品比較。分析方法使用交流阻抗(electronic impedance spectroscopy; EIS)測定離子傳導性並以阿瑞尼士法(Arrhenius plot)推算鋰離子傳導之活化能、X光吸收光譜(X-ray absorption spectroscopy; XAS)與X光光電子能譜(X-ray photoelectron spectroscopy; XPS) 測量各元素之價數與化學環境與掃描式電子顯微鏡(scanning electron microscope; SEM)檢視成品緻密度。未經伏安循環鋰鑭鋯氧之傳導度約為3.0 x 10-4 S/cm，伏安循環法可提升至約1.3 x 10-3 S/cm，近5倍之多。X光繞射與X光吸收光譜同時指出鋰離子占有位置於伏安循環前後產生變化。配合Li2Ni0.5Co0.2Mn0.3O2材料組裝全固態鋰離子電池並以0.21 mA/cm2之電流密度初步獲得約60 mAh/g之電容量，証明所生產之固態電解質之應用性。

關鍵字

石榴石；固態電解質；鋰鑭鋯氧；伏安循環法

並列摘要

In this study, solid state electrolyte, aluminum doped lithium lanthanum zirconium oxide (Li7La3Zr2O12, LLZO) without doping any expensive element, such as Tantalum, was synthesized. X-ray diffraction spectroscopy (XRD) was conducted to confirm that LLZO synthesized is cubic phase. Cyclic voltammetry (CV) was used to enhance the ionic conductivity of LLZO and the samples were compared with the ones without CV treatment. The following analytical methods were conducted. Electronic impedance spectroscopy (EIS) was used to evaluate ionic conductivity; Arrhenius plots were conducted to deduce migration activation energy of lithium ions; X-ray adsorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) were done to determine chemical states of different elements; scanning electron microscope (SEM) was used to evaluate density of LLZO pellets. The LLZO with CV treatment has conductivity of 1.3 x 10-3 S/cm, which is almost five times higher than the one without CV treatment (3.0 x 10-4 S/cm). Both XAS and XPS data reveal that there is a change of coordinate of lithium ions after CV treatment. Full solid state lithium ion battery was successfully assembled using the LLZO, along with Li2Ni0.5Co0.2Mn0.3O2 cathode material and Li metal anode, and acquired the capacity of 60 mAh g-1 under the current density of 0.21 mA cm-1. This proves the potential industrial applicability of solid state electrolytes.

並列關鍵字

Garnet ； solid state electrolyte ； LLZO ； Li7La3Zr2O12 ； lithium lanthanum oxide ； cyclic voltammetry

參考文獻

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石榴石型鋰離子導體於鋰離子電池之應用

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