高比表面積二氧化鈦於鈉離子電池陽極之應用

Abstract

在眾多能源課題中，鋰離子電池的蓬勃發展使得需求量大幅增加，必須面對其價格昂貴以及受到地區性限制的缺點，而鈉金屬在地表上含量豐富，不受地區限制，使得鈉離子電池具有低成本的特性，並且與鋰為同族，因此被視為可替代鋰離子電池之新能源技術。其中，由於二氧化鈦無毒、低成本，且體積膨脹變化較小等特性，被視為鈉離子電池中最具有潛力的陽極材料之一。在此研究中，我們藉由溶劑熱法，與兩種低成本、對環境無害之鹼性胺基酸生物原料: 精氨酸和麩胺酸鈉(味精)反應，水解縮合並進一步鍛燒，而產生空心片狀球及實心片狀球。產物的特性鑑定主要使用掃描式電子顯微鏡、穿透式電子顯微鏡、粉末型X光繞射技術及氮氣吸脫附分析技術。吸脫附曲線結果顯示其表面積分別為116及91 m2/g。應用在鈉離子電池的表現方面，由表面積較大的空心片狀球表現最為優異，在0.1 C (1 C = 335 mA/g)的充放電速度下經過100次循環後有145 mAh/g的電容值，在高速充放電下2 C和5 C分別可以達到85 mAh/g及62 mAh/g，電池在經由多次充放電後穩定性及效能皆呈現不錯的表現，結果顯示此材料是有潛力作為鈉離子電池之陽極材料。

Among the various battery technologies, lithium ion battery (LIB) is quite mature but there were questions regarding increasing prices of Li mineral reserves and disadvantage in a few specific locations. However, sodium is substantially less expensive, more abundant than lithium which let sodium ion batteries have been considered as a desirable alternative to LIB. Among the known materials, TiO2 is regarded as powerful candidates due to the non-toxic, low cost, and small volume change during Na+ ion insertion. In this study, facile route was established to synthesize high specific surface area TiO2 microspheres by using amino acids (arginine and monosodium glutamate) as the assistances. The solvothermal method was carried out in a heated Teflon stainless-steel autoclave. The as-synthesized TiO2 were further processed at 400 °C under air to generate the nanosheet spheres (NS) and solid spheres with nanosheets (SS). They were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and nitrogen adsorption-desorption analysis. The isotherms revealed specific surface areas were 116 and 91 m2/g, respectively. The products were used as anodes for Na ion battery. The cells of NS showed a reversible capacity 145 mAh/g after 100 discharge/charge cycles at a current density of 0.1 C (1 C = 335 mA/g). The anode reached 85 mAh/g and 62 mAh/g under high rates, 2 C and 5 C respectively. The results showed that high specific surface area TiO2 exhibited good reversible capacity and cyclic stability as promising candidates as anodes for sodium ion batteries.