【摘要】：鋰離子電池因具有環(huán)境友好、工作電壓高、比能量大、循環(huán)壽命長(zhǎng)等優(yōu)點(diǎn)在儲(chǔ)能領(lǐng)域的性價(jià)比突出,已迅速成為研發(fā)的熱點(diǎn)。當(dāng)前市場(chǎng)上的負(fù)極材料主要是以石墨為主的傳統(tǒng)炭材料,而石墨理論的比容量較低,這大大阻礙了高性能鋰離子電池的快速發(fā)展。本文以三種不同的生物質(zhì)為碳源,通過(guò)低溫炭化、高溫石墨化和化學(xué)活化等方法對(duì)生物質(zhì)炭材料進(jìn)行綜合處理,改善炭材料的表面形貌和微觀結(jié)構(gòu)。采用了X射線衍射(XRD)、拉曼光譜(Raman)、掃描電子顯微鏡(SEM)等測(cè)試從而對(duì)材料的結(jié)構(gòu)及形貌進(jìn)行分析。并且將制備得到的炭材料作為負(fù)極材料組裝成扣式電池。為研究材料的結(jié)構(gòu)對(duì)電化學(xué)性能的影響,進(jìn)行了恒流充放電測(cè)試、循環(huán)伏安測(cè)試和電化學(xué)交流阻抗測(cè)試。研究發(fā)現(xiàn),微藻在900℃低溫炭化得到的炭材料擁有適宜的多級(jí)孔結(jié)構(gòu)和石墨結(jié)構(gòu),而且在充放電過(guò)程中形成的SEI膜完整性和穩(wěn)定性好,因而材料表現(xiàn)出最優(yōu)異的電化學(xué)性能。豆渣在2800℃熱處理后石墨化程度明顯提高,在0.1 C倍率下循環(huán)100次后容量從423 mAh g-1下降到396 mAh g-1,表現(xiàn)出優(yōu)秀的循環(huán)性能;豆渣經(jīng)過(guò)化學(xué)活化處理后電化學(xué)性能明顯改善,特別是KOH處理后的樣品,在0.1 C下首次充電容量高達(dá)801 mAh g-1,甚至在1 C下容量還有643 mAh g-1,循環(huán)500次后容量保持率高達(dá)94%,這優(yōu)異的電化學(xué)性能取決于它高比表面積和豐富的介孔結(jié)構(gòu)。同樣以KOH為活化劑,茶籽殼炭化活化得到的炭材料的電化學(xué)性能優(yōu)于水熱活化,這也是由于它更高的比表面積和更發(fā)達(dá)的孔隙結(jié)構(gòu)導(dǎo)致的。
[Abstract]:Li-ion battery has become a hot research and development field because of its advantages such as friendly environment, high working voltage, large specific energy, long cycle life and so on, which has outstanding performance-price ratio in the field of energy storage. At present, the anode materials in the market are mainly traditional carbon materials based on graphite, but the specific capacity of graphite theory is relatively low, which greatly hinders the rapid development of high-performance lithium ion batteries. In this paper, three kinds of biomass were used as carbon source to improve the surface morphology and microstructure of carbon materials by means of low temperature carbonization, high temperature graphitization and chemical activation. X-ray diffraction (XRD) (XRD), Raman spectroscopy (XRD),) (Raman), scanning electron microscope (SEM) was used to analyze the structure and morphology of the materials. The prepared carbon material is assembled as a negative electrode material to form a button battery. In order to study the influence of structure on electrochemical performance, constant current charge-discharge test, cyclic voltammetry test and electrochemical impedance test were carried out. It was found that the carbon material obtained from the carbonization of microalgae at 900 鈩，

本文編號(hào)：2308785