Relations Between Microstructures and Performance of Oxide Electrodes in Electrochemical Double Layer Capacitors

影響二氧化錫電極之比電容量包含了三大 因素：粉體之表面積、粉體之孔洞分布、 粉體之結晶度。隨著熱處理溫度之升高， 粉體之晶粒大小亦隨之成長，較高結晶度 有助於粉體導電度之提高。其孔徑大小逐 漸變大，較大之孔洞有助於電解質中離子 之傳導。但此過程中，可供離子吸附以產 生電荷分離之比表面積卻隨之減少。此三 因素之間相互影響，並無法同時兼顧，因 此其中必定存在一個最適當之條件。由實 驗結果，我們可得知的是，在最適溫度 500 o C 下進行熱處理，可以取得最大的可供電化學反應表面積。This research focuses on the preparation of sol-gel derived Sb-doped SnO2 xerogel and aerogel with high surface area. By mixing these powders with binder and then coating on substrate, the performance of the film electrode of a supercapacitor in conjunction with KOH electrolyte have been evaluated. Powders heat-treated at temperatures below 400 o C exhibited strongly distributed-capacity phenomenon due to their small pores. Powders heat-treated at temperatures above 600 o C have low capacity due to their small surface area. The optimum heat-treatment temperature for maximum capacitance is ~ 500 o