離子電池因為能量密度高以及無記憶效應等優點，已成為現今商用二次電池的大宗，尤以鋰離子電池為主流。然而，由於鋰礦資源稀缺性導致電池成本居高不下，鋰電池又普遍存有生成鋰枝晶的問題，加上目前商用電池大多採用有機電解液，具易燃性以及高揮發性，若使用不當有漏液，甚至造成爆炸的隱憂，故開發新型態的離子電池以及採用環保無毒的固態電解質成為目前儲能領域發展的方向。在眾多離子電池中，鉀離子電池被視為非常有潛力能成為下一代新興儲能電池的主流之一，除了因為鉀礦資源的豐厚性，為目前地殼中含量第七大的元素，鉀的還原電位 (K+/ K: -2.93 V)與鋰 (Li+/ Li: -3.04 V)相去不遠，使其具備較高的工作電壓以及能量密度等優點。
本研究為建構全固態鉀離子電池，首先在正極方面分為兩種，第一部分為固相反應法合成的鉀錳氧 (KMO)化合物，第二部分為透過富鉀處理製成的磷酸鐵鉀 (KFPO)正極材料，負極則是採用石墨，並先是以鈉基矽酸鹽作為固態電解質。實驗結果顯示，兩種正極材料皆能有效的進行循環充放電測試，也驗證固相反應法以及富鉀處理兩種正極材料製程之有效性。因此本研究進一步導入了明礬作為新型態的固態電解質，並探討其與鈉基矽酸鹽之間差異性。
在確立了全固態鉀離子電池系統的組構設計後，進一步對其進行溫度效應測試，實驗結果顯示，全固態鉀離子電池在高溫55℃雖然會使最大放電電容量提升，但是循環穩定度較低；低溫-15℃則是電容量下降許多，但保有良好循環穩定度，此現象主要是工作溫度高低影響離子傳導速率。透過探討各電解質於高溫55℃與低溫-15℃下的實際應用情形，輔以一系列的電化學相關測試以及對材料本身性質分析，藉此釐清正、負極之間離子傳遞情形，並建構出全電池的電化學反應機制。
本研究採用鉀基正極材料、石墨負極，搭配鈉基矽酸鹽以及明礬作為新型態的固態電解質，成功建構出全固態鉀離子電池，在眾多非鋰系的離子電池中，除了展現良好的充放電表現與穩定性，同時還具有高安全性以及對環境友善等優勢，相關研究成果可供儲能領域參考。

關鍵字：鉀電池、鉀錳氧、磷酸鐵鉀、固態電解質、充放電

Due to the advantages of high energy density and no memory effect, lithium-ion batteries have become the most widely used type of commercial batteries. However, due to the problem of scarcity of lithium mineral resources and forming of lithium dendrites, potassium-ion batteries are introduced in this study. Potassium is the seventh most abundant element in the earth’s crust and its reduction potential (K+/ K: -2.93 V) is not far from lithium (Li+/ Li: -3.04 V), which makes it have the advantages of higher working voltage and energy density. In addition, solid-state electrolyte is introduced in this study to solve the risk of leakage or explosion from the liquid electrolyte.
The potassium cathode materials are made of two different processes. K0.5MnO2 synthesized by solid-state reaction, and KFePO4 made by potassium enrichment. We first evaluate two cathodes with sodium silicate electrolyte and graphite anode as solid-state batteries, and the results show that both materials can perform well as cathodes. Therefore, we further introduced alum as a new type of solid-state electrolyte and explored the difference between it and sodium silicate.
After the establishment of the all-solid-state potassium-ion batteries, the temperature effect test showed that it has the best performance at room temperature. Although the capacity will be increased at 55°C, it also decays faster because of structural collapse and water dissipation in the electrolyte. The capacity is decreased while the cycle stability is increased at -15°C, which is due to the effect of lower mobility of conducting ions. By exploring the situation of each electrolyte at different temperature, supplemented by a series of electrochemical tests and analysis, the ion intercalation mechanism between electrolyte and anode is clarified and constructed.
In the end, potassium cathodes, graphite anode, sodium silicate and alum are used to successfully construct all-solid-state potassium-ion batteries, which show good cycle performance, high safety, and environmental-friendly.

Keywords: Potassium-ion batteries, K0.5MnO2, KFePO4, Solid-state electrolyte, Charge-discharge

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