本文關(guān)鍵詞： 碳基 納米 鋰離子 電池 中的 應(yīng)用 研究　出處：《南京大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：碳材料具有導(dǎo)電性好、電化學(xué)／機(jī)械穩(wěn)定性優(yōu)異、質(zhì)量輕、價(jià)格低廉及環(huán)境友好等優(yōu)點(diǎn),廣泛用作鋰離子電池的負(fù)極材料、正極材料改性劑、導(dǎo)電劑等。商用石墨存在比容量不夠高和不耐大電流充放電等不足,具有有利于傳質(zhì)和電子傳輸?shù)男滦腿S分級(jí)結(jié)構(gòu)碳納米材料日益受到重視。最近,我們課題組發(fā)展了一種制備碳基納米籠的方法,其具有高比表面積、分級(jí)孔結(jié)構(gòu)和良好導(dǎo)電性等特征,用作超級(jí)電容器電極材料和陰極氧還原無金屬催化劑表現(xiàn)出優(yōu)異的性能。本論文在碳基納米籠的可控制備、鋰離子電池電極材料導(dǎo)向的應(yīng)用基礎(chǔ)研究方面取得較好進(jìn)展：(1)碳納米籠負(fù)載LiFePO4作為鋰離子電池正極材料：以苯為前驅(qū)物、原位生成的氧化鎂為模板,制備出具有大比表面積(1274 m2 g-1)、高導(dǎo)電率(1.44 Scm-1)和分級(jí)孔結(jié)構(gòu)的碳納米籠((CNCs)。以CNCs為載體,構(gòu)建出LiFePO4/CNCs復(fù)合材料,粒徑約為10-25 nm的LiFePO4納米粒子均勻分散在CNCs載體表面,其體相電導(dǎo)率為0.53 S cm-1,顯著高于純相LiFePO4的2.27×10-9 S cm-1。以LiFePO4/CNCs復(fù)合物作為鋰離子電池的正極材料,在0.1 C下放電比容量可達(dá)163 mAh g-1,接近LiFePO4的理論比容量；在15 C和30 C高倍率下,放電比容量可達(dá)96和75 mAh g-1,15 C倍率下循環(huán)200圈后比容量為92 mAh g-1,即LiFePO4/CNCs復(fù)合物具有優(yōu)異的倍率性能和循環(huán)穩(wěn)定性。(2)氮摻雜碳納米籠作為鋰離子電池負(fù)極材料：以吡啶為前驅(qū)物、原位生成的氧化鎂為模板制備出類似于上述CNCs結(jié)構(gòu)特征的氮摻雜碳納米籠(NCNCs)。以NCNCs作為鋰離子電池負(fù)極材料,在0.1 A g-1電流密度下,NCNC700、 NCNC800和NCNC900比容量依次為710、900和700 mAh g-1,這可歸因于800℃下合成的NCNCs兼具較好的導(dǎo)電性和較大的比表面積。在高電流密度10 A g-1和20Ag-1下,NCNC800的比容量分別達(dá)到200 mAh g-1和100 mAh g-1,且在大電流密度下循環(huán)600圈后容量無明顯降低�？梢�,NCNCs是一種優(yōu)良的鋰離子電池負(fù)極材料。
[Abstract]:Carbon has the advantages of good conductivity, excellent electrochemical / mechanical stability, light weight, low price and environmental friendliness. It is widely used as anode material and modifier for lithium ion batteries. Commercial graphite has insufficient specific capacity and low resistance to charge and discharge of large current, and has been paid more and more attention to the new three-dimensional graded structure carbon nanomaterials which are beneficial to mass transfer and electron transport. Our team has developed a method for preparing carbon based nanocages, which has the characteristics of high specific surface area, graded pore structure and good electrical conductivity. As electrode material of supercapacitor and cathode oxygen reduction metal-free catalyst, this paper presents excellent performance. Good progress has been made in the application of electrode material orientation in lithium ion battery. (1) carbon nanocage supported LiFePO4 is used as cathode material for lithium ion battery: benzene is used as precursor. In situ, magnesium oxide was used as a template to produce a large specific surface area of 1274 m2 / g ~ (-1). High conductivity (1.44 Scm-1) and carbon nanocage with graded pore structure were used to fabricate LiFePO4/CNCs composites with CNCs as the carrier. LiFePO4 nanoparticles with a particle size of about 10-25 nm were uniformly dispersed on the surface of the CNCs support, and the bulk conductivity was 0.53S cm-1. It is significantly higher than that of pure phase LiFePO4 (2.27 脳 10 ~ (-9) S cm ~ (-1)). LiFePO4/CNCs complex is used as cathode material of lithium ion battery. At 0.1C, the discharge specific capacity can reach 163 mAh g-1, which is close to the theoretical specific capacity of LiFePO4. At 15 C and 30 C, the specific discharge capacity is 92 mAh g ~ (-1) at the rate of 96 and 75 mAh / g ~ (-1) ~ (15) C, and the specific capacity is 92 mAh / g ~ (-1) after cycling for 200 cycles. That is, LiFePO4/CNCs composite has excellent rate performance and cycle stability. 2) nitrogen doped carbon nanocage is used as anode material for lithium ion battery. Pyridine is used as precursor. The N-doped carbon nanocage (NCNCsN) with NCNCs as anode material for lithium-ion batteries was prepared by in-situ MgO as a template, which is similar to the above CNCs structure. At the current density of 0.1 A g ~ (-1), the specific capacities of NCNC800 and NCNC900 were 710,900 and 700 mAh / g ~ (-1), respectively. This can be attributed to the good conductivity and large specific surface area of NCNCs synthesized at 800 鈩，

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