基于層狀氫氧化物層間限域空間可控制備碳基納米材料及其電化學(xué)性能研究
發(fā)布時(shí)間：2018-08-11 12:24
【摘要】：隨著化石燃料的不斷消耗,能源危機(jī)和環(huán)境污染越來(lái)越嚴(yán)重,對(duì)人類健康、能源安全和環(huán)境保護(hù)提出了更為嚴(yán)峻的挑戰(zhàn),因此迫切需要發(fā)展新型清潔能源。燃料電池和鋰離子電池具有環(huán)境污染小、能量轉(zhuǎn)換效率高等優(yōu)點(diǎn),作為有效的清潔電源有望解決上述問題,但提高燃料電池和鋰離子電池電化學(xué)性能的關(guān)鍵在于開發(fā)具有優(yōu)異性能的電極材料。本論文利用層狀氫氧化物的層間限域空間可控制備了一系列摻雜碳基納米材料,考察了合成工藝與材料結(jié)構(gòu)之間的關(guān)系規(guī)律,對(duì)其氧還原(ORR)電催化和鋰存儲(chǔ)性能進(jìn)行了測(cè)試和評(píng)估,并深入地研究了材料結(jié)構(gòu)和電化學(xué)性能之間的內(nèi)在關(guān)系。主要研究?jī)?nèi)容如下:1、基于鎂鋁水滑石(MgAl-LDH)層間二維限域效應(yīng),制備了選擇性氮硫雙摻雜碳納米片(NSCNs),并對(duì)其氧還原電催化和鋰存儲(chǔ)性能及機(jī)制進(jìn)行了研究。首先將間氨基苯磺酸根陰離子通過一步水熱法插入MgAl-LDH層間,再通過高溫碳化和酸化刻蝕實(shí)現(xiàn)了 NSCNs的可控制備,獲得的NSCNs由大量相互連接的納米片組成,呈現(xiàn)出豐富的多級(jí)微介孔和高的比表面積。LDH的層間二維限域效應(yīng)不僅促進(jìn)了具有平結(jié)構(gòu)的吡啶N和吡咯N的形成(達(dá)到90.3%),而且有效地緩解了高溫下N原子和S原子的損失,提高了雜原子摻雜量。用作ORR電催化劑,NSCNs在堿性介質(zhì)中表現(xiàn)出高的催化活性,與商業(yè)Pt/C催化劑相比,具有更好的抗甲醇毒化能力和穩(wěn)定性。用作鋰離子電池負(fù)極材料,NSCNs表現(xiàn)出超高的比容量(在電流密度0.2 A·g-1下循環(huán)110周后比容量可達(dá)2240 mAh·g-1),優(yōu)異的倍率性能(在電流密度4.0A·g-1下比容量為983 mAh·g-1)和長(zhǎng)久的穩(wěn)定性(在電流密度4.0 A·g-1下循環(huán)500周后的可逆比容量仍達(dá)到950mAh·g-1)。此外,XPS結(jié)果和DFT理論計(jì)算結(jié)果表明在循環(huán)過程中摻雜的吡咯N原子能夠和Li+結(jié)合形成Li3N并從摻雜碳上脫落,同時(shí)在鄰近吡咯N原子的位點(diǎn)形成更多的邊緣C原子用于儲(chǔ)鋰,而吡啶N和季N原子不能發(fā)生像吡咯N原子那樣的脫落。2、基于CoAl-LDH層間二維限域效應(yīng),制備了 Co9S8/氮摻雜碳納米片基空心球復(fù)合物(Co9S8/NHCS),并對(duì)其氧還原催化活性進(jìn)行了研究。首先將間氨基苯磺酸根陰離子通過一步水熱法插入CoAl-LDH層間,再通過高溫碳化和選擇性酸化刻蝕制備了 Co9S8/NHCS,獲得的Co9S8/NHCS具有由大量納米片組成的空心球狀結(jié)構(gòu),其中單分散的Co9S8植入碳納米片中。此結(jié)構(gòu)主要有以下優(yōu)勢(shì):基于層間二維限域方法獲得了單分散的Co9S8顆粒,使Co9S8的催化活性位點(diǎn)能夠被充分地暴露和利用,因而具有高的催化活性;間氨基苯磺酸根陰離子的分解碳化和Co9S8的生成同時(shí)發(fā)生,使得生成的Co9S8納米顆粒能夠植入碳納米片中,因而具有高的穩(wěn)定性;前驅(qū)體的空心球狀結(jié)構(gòu)使得制備的Co9S8/NHCS也具有獨(dú)特的空心球狀結(jié)構(gòu)和多級(jí)孔結(jié)構(gòu),有助于在催化過程中促進(jìn)電解質(zhì)離子、反應(yīng)中間體和產(chǎn)物的快速傳輸。此外,本工作系統(tǒng)地研究了焙燒溫度和空心球狀結(jié)構(gòu)對(duì)催化劑結(jié)構(gòu)(如比表面積、孔分布、氮摻雜類型、Co9S8的尺寸大小等)和催化活性的影響,結(jié)果表明900 ℃是優(yōu)化的焙燒溫度且空心球狀結(jié)構(gòu)對(duì)ORR催化活性的提高具有非常重要的作用。電化學(xué)測(cè)試表明在900℃下制備的Co9S8/NHCS催化劑在堿性和酸性介質(zhì)中均具有最高的ORR催化活性、持久的穩(wěn)定性和優(yōu)異的抗甲醇毒化能力。3、基于CoAl-LDH層間二維限域效應(yīng),制備了含有Co-Nx組分的碳納米片基空心球復(fù)合物(Co-N/C),并對(duì)其在不同pH介質(zhì)中的氧還原催化活性和活性位點(diǎn)進(jìn)行了研究。首先將間氨基苯磺酸根陰離子通過一步水熱法插入CoAl-LDH層間,再通過高溫碳化和酸化刻蝕制備了 Co-N/C。獲得的Co-N/C具有由大量含有Co-Nx組分的碳納米片組成的空心球狀結(jié)構(gòu),呈現(xiàn)出豐富的微介孔和高的比表面積。作為ORR電催化劑,對(duì)其在不同pH介質(zhì)中的催化活性進(jìn)行了測(cè)試,電化學(xué)數(shù)據(jù)表明在900℃下制備的Co-N/C催化劑具有最高的ORR催化活性,在堿性和中性介質(zhì)中表現(xiàn)出高的半波電位和大的極限擴(kuò)散電流,該性能和商業(yè)Pt/C催化劑相當(dāng),同時(shí)表現(xiàn)出優(yōu)異的穩(wěn)定性和抗甲醇毒化能力。通過在不同pH介質(zhì)中研究掩蔽離子(SCN-和F-)對(duì)Co原子中心進(jìn)行毒化前后的ORR催化活性以及比較Co-N/C催化劑的Co-Nx位點(diǎn)破壞前后的ORR催化活性,發(fā)現(xiàn)在堿性介質(zhì)中,Co-N/C催化劑的催化活性沒有明顯地變化,而在中性和酸性介質(zhì)中,Co-N/C催化劑的催化活性明顯地降低,說(shuō)明Co-N/C催化劑中的Co-Nx位點(diǎn)在中性和酸性介質(zhì)中直接作為ORR催化活性位點(diǎn),而在堿性條件下對(duì)催化活性的影響是可忽略的。4、基于Co(OH)2層間二維限域效應(yīng),制備了硫化鈷和氮摻雜碳納米片基花狀復(fù)合物(Co9S8/CO1-xS@]NC),并對(duì)其形成機(jī)理和鋰存儲(chǔ)性能進(jìn)行了研究。首先將間氨基苯磺酸根陰離子通過一步水熱法插入Co(OH)2層間,再將具有插層結(jié)構(gòu)的Co(OH)2前驅(qū)體與硫粉均勻混合后在N2氣氛下焙燒得到Co9S8/Co1-xS@NC。獲得的Co9S8/Co1-xS@NC具有由大量植入小尺寸硫化鈷納米顆粒的氮摻雜碳納米片組成的花狀形貌,并且在硫化鈷顆粒外表面覆蓋有幾層石墨烯。通過對(duì)插層結(jié)構(gòu)的Co(OH)2前驅(qū)體的碳化/硫化機(jī)理進(jìn)行詳細(xì)地研究,發(fā)現(xiàn)間氨基苯磺酸根離子分解碳化形成碳納米片發(fā)生在約200 ℃-400 ℃,在這個(gè)過程中伴隨著S的升華、Co(OH)2層的分解和Co1-xS納米顆粒的生成,所以Co1-xS納米顆�？梢灾踩朐谔技{米片中。隨著焙燒溫度的增加,部分Co1-xS逐漸向Co9S8轉(zhuǎn)變,同時(shí)碳納米片的石墨化程度進(jìn)一步提高。此結(jié)構(gòu)主要有以下優(yōu)勢(shì):具有小尺寸的硫化鈷能夠縮短鋰離子的傳輸距離和緩解脫嵌鋰過程中產(chǎn)生的體積應(yīng)力,這有助于提高電極的循環(huán)穩(wěn)定性和倍率性能;氮摻雜的碳基質(zhì)和硫化鈷外表面覆蓋的幾層石墨烯不僅可以防止顆粒之間的聚集和減小顆粒之間的電阻,而且可以有效地緩解在充放電循環(huán)過程中硫化鈷的體積膨脹和多硫化物在電解液中的溶解,因此有助于提高電極的循環(huán)穩(wěn)定性;薄的顆粒-納米片結(jié)構(gòu)可以減少離子和電子的傳輸距離,使得硫化鈷納米顆粒被充分地利用,因此有助于獲得高的比容量;具有大比表面積的花狀形貌和多級(jí)孔結(jié)構(gòu)能夠促進(jìn)電解液進(jìn)入電極內(nèi)部,加快鋰離子的傳遞。此外,通過調(diào)變前驅(qū)體和硫粉的比例或焙燒溫度可有效地控制硫化鈷的組成。作為鋰離子電池負(fù)極材料,電化學(xué)測(cè)試表明在900 ℃,且前驅(qū)體和硫粉的質(zhì)量比為1:0.75時(shí)制備的Co9S8/Co1-xS@NC表現(xiàn)出高的比容量和優(yōu)異的倍率性能。本論文提出的基于層狀氫氧化物層間限域合成方法可拓展到制備其它具有優(yōu)異性能的功能性摻雜碳基納米材料,并在超級(jí)電容器、太陽(yáng)能電池、傳感器、環(huán)境保護(hù)、催化等領(lǐng)域表現(xiàn)出廣闊的應(yīng)用前景。
[Abstract]:With the continuous consumption of fossil fuels, the energy crisis and environmental pollution are becoming more and more serious, which poses a more serious challenge to human health, energy security and environmental protection. Therefore, it is urgent to develop new clean energy sources. Fuel cells and lithium-ion batteries have the advantages of less environmental pollution, high energy conversion efficiency, and so on, as an effective cleaner. In this paper, a series of doped carbon-based nanomaterials were synthesized by controlling the interlayer confinement space of layered hydroxides, and the relationship between the synthesis process and the structure of the materials was investigated. The main research contents are as follows: 1. Selective Nitrogen-Sulfur double-doped carbon nanosheets (NSCNs) were prepared based on the two-dimensional confinement effect between MgAl-LDH layers, and their oxygen content was determined. The reductive electrocatalysis and lithium storage properties and mechanisms were studied. The m-aminobenzenesulfonate anion was first inserted into the MgAl-LDH interlayer by one-step hydrothermal method, and then controlled preparation of NSCNs was realized by high temperature carbonization and acidification etching. The obtained NSCNs consisted of a large number of interconnected nanosheets, showing rich multistage mesoporous and high-level. Specific surface area. The two-dimensional interlayer confinement effect of LDH not only promotes the formation of pyridine N and pyrrole N with flat structure (up to 90.3%), but also effectively alleviates the loss of N and S atoms at high temperature and increases the amount of heteroatom doping. As an ORR electrocatalyst, NSCNs exhibit high catalytic activity in alkaline medium and commercial Pt/C catalyst. NSCNs, as anode materials for lithium-ion batteries, exhibit super-high specific capacity (after 110 weeks of cycling at current density of 0.2 A g-1), excellent rate performance (at current density of 4.0 A g-1, specific capacity of 983 mAh g-1) and long-term stability (at current density of 4.0 A g-1). In addition, XPS and DFT calculations show that the doped pyrrole N atoms can bind to Li + to form Li3N and fall off the doped carbon during the cycling process. At the same time, more edge C atoms are formed at the sites adjacent to the pyrrole N atoms for lithium storage. Pyridine N and quaternary N atoms can not fall off like pyrrole N atoms. 2. Co9S8/N-doped carbon nanosheet-based hollow sphere composite (Co9S8/NHCS) was prepared based on CoAl-LDH interlayer two-dimensional confinement effect, and its catalytic activity for oxygen reduction was studied. Firstly, m-aminobenzenesulfonate anion was inserted into CoAl-LDH by one-step hydrothermal method. Co9S8/NHCS was prepared by high temperature carbonization and selective acidification etching. The obtained Co9S8/NHCS has a hollow spherical structure consisting of a large number of nanosheets, in which monodisperse Co9S8 was implanted into carbon nanosheets. The structure has the following advantages: monodisperse Co9S8 particles were obtained based on the two-dimensional finite-region method, which prompted the formation of Co9S8 particles. The decomposition and carbonization of m-aminobenzenesulfonate anion and the formation of Co9S8 occur simultaneously, which makes the Co9S8 nanoparticles implanted into carbon nanosheets and thus has high stability. The hollow spherical structure of the precursor makes the prepared Co9S8/NHCS highly stable. In addition, the effects of calcination temperature and hollow spherical structure on the structure of the catalysts (such as specific surface area, pore distribution, nitrogen doping type, size and size of Co9S8) and The results showed that 900 C was the optimum calcination temperature and the hollow spherical structure played a very important role in enhancing the catalytic activity of ORR. Electrochemical tests showed that the CO9S8/NHCS catalysts prepared at 900 C had the highest ORR catalytic activity in both alkaline and acidic media, long-term stability and excellent anti-A activity. Alcohol toxicity. 3. Carbon nanosheet-based hollow sphere composites (Co-N/C) containing Co-Nx components were prepared based on the two-dimensional confinement effect of C oAl-LDH layers. The catalytic activity and active sites of the hollow sphere composites in different pH media were studied. The anions of m-aminobenzenesulfonate were firstly inserted into the layers of C oAl-LDH by one-step hydrothermal method and then recanalized. Co-N/C was prepared by carbonization and acidification etching at high temperatures. The obtained Co-N/C has a hollow spherical structure consisting of a large number of carbon nanosheets containing Co-Nx components, showing abundant mesopores and high specific surface area. As an ORR electrocatalyst, its catalytic activity in different pH media was tested. The electrochemical data showed that the Co-N/C had a hollow spherical structure at 900 C. The prepared C o-N/C catalyst exhibited the highest ORR activity, high half-wave potential and high limiting diffusion current in alkaline and neutral media. The performance of the catalyst was similar to that of commercial Pt/C catalyst, and showed excellent stability and anti-methanol toxicity. The ORR catalytic activity of Co-N/C catalyst before and after poisoning and the ORR catalytic activity of Co-N/C catalyst before and after destruction of Co-Nx site were compared. It was found that the catalytic activity of Co-N/C catalyst did not change significantly in alkaline medium, but in neutral and acidic medium, the catalytic activity of Co-N/C catalyst decreased significantly, indicating that the Co-N catalytic activity of Co-N/C catalyst decreased significantly. The x site acts as ORR active site directly in neutral and acidic media, but the effect on ORR catalytic activity is negligible under alkaline conditions. 4. Based on the two-dimensional confinement effect between CO(OH)2 layers, cobalt sulfide and nitrogen-doped carbon nano-flake-based flower composite (Co9S8/CO1-xS@) NC were prepared, and its formation mechanism and lithium storage properties were studied. Co9S8/Co1-xS@NC was prepared by mixing the intercalated Co(OH)2 precursor with sulfur powder and calcining it in N2 atmosphere. The obtained Co9S8/Co1-xS@NC consisted of a large number of nitrogen-doped carbon nanosheets embedded in small size cobalt sulfide nanoparticles. The intercalated Co (OH) 2 precursor was carbonized and vulcanized. It was found that the carbonization of m-Aminobenzene sulfonate ion to form carbon nanosheets occurred at about 200 ~400 ~C, accompanied by S sublimation and Co (OH) 2 layer. Co1-xS nanoparticles can be implanted in carbon nanosheets because of the decomposition and the formation of Co1-xS nanoparticles. With the increase of calcination temperature, some of Co1-xS is gradually transformed to Co9S8, and the graphitization degree of carbon nanosheets is further improved. Separation and relaxation of the volume stress produced in the process of lithium removal are helpful to improve the cyclic stability and rate performance of the electrode; nitrogen-doped carbon matrix and several layers of graphene coated on the outer surface of cobalt sulfide can not only prevent the aggregation of particles and reduce the resistance between particles, but also effectively alleviate the charge-discharge cycle process. The volume expansion of medium cobalt sulfide and the dissolution of polysulfide in electrolyte are helpful to improve the cyclic stability of the electrode; the thin particle-nanosheet structure can reduce the ion and electron transport distances, making the cobalt sulfide nanoparticles fully utilized, thus contributing to high specific capacity; the flower-like structure with large specific surface area The morphology and pore structure can promote the electrolyte to enter the electrode and accelerate the transfer of lithium ions. In addition, the composition of cobalt sulfide can be effectively controlled by changing the ratio of the precursor and sulfur powder or calcination temperature. As the anode material of lithium-ion batteries, the electrochemical tests show that the electrolyte is at 900 C and the mass ratio of the precursor and sulfur powder is 1:0.75. The prepared Co9S8/Co1-xS@NC exhibits high specific capacity and excellent rate performance. The method based on interlayer limiting synthesis of layered hydroxides proposed in this paper can be extended to prepare other functionally doped carbon-based nanomaterials with excellent properties, and can be used in supercapacitors, solar cells, sensors, environmental protection, catalysis and other fields. It has broad application prospects.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.1
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本文編號(hào)：2176984
[Abstract]:With the continuous consumption of fossil fuels, the energy crisis and environmental pollution are becoming more and more serious, which poses a more serious challenge to human health, energy security and environmental protection. Therefore, it is urgent to develop new clean energy sources. Fuel cells and lithium-ion batteries have the advantages of less environmental pollution, high energy conversion efficiency, and so on, as an effective cleaner. In this paper, a series of doped carbon-based nanomaterials were synthesized by controlling the interlayer confinement space of layered hydroxides, and the relationship between the synthesis process and the structure of the materials was investigated. The main research contents are as follows: 1. Selective Nitrogen-Sulfur double-doped carbon nanosheets (NSCNs) were prepared based on the two-dimensional confinement effect between MgAl-LDH layers, and their oxygen content was determined. The reductive electrocatalysis and lithium storage properties and mechanisms were studied. The m-aminobenzenesulfonate anion was first inserted into the MgAl-LDH interlayer by one-step hydrothermal method, and then controlled preparation of NSCNs was realized by high temperature carbonization and acidification etching. The obtained NSCNs consisted of a large number of interconnected nanosheets, showing rich multistage mesoporous and high-level. Specific surface area. The two-dimensional interlayer confinement effect of LDH not only promotes the formation of pyridine N and pyrrole N with flat structure (up to 90.3%), but also effectively alleviates the loss of N and S atoms at high temperature and increases the amount of heteroatom doping. As an ORR electrocatalyst, NSCNs exhibit high catalytic activity in alkaline medium and commercial Pt/C catalyst. NSCNs, as anode materials for lithium-ion batteries, exhibit super-high specific capacity (after 110 weeks of cycling at current density of 0.2 A g-1), excellent rate performance (at current density of 4.0 A g-1, specific capacity of 983 mAh g-1) and long-term stability (at current density of 4.0 A g-1). In addition, XPS and DFT calculations show that the doped pyrrole N atoms can bind to Li + to form Li3N and fall off the doped carbon during the cycling process. At the same time, more edge C atoms are formed at the sites adjacent to the pyrrole N atoms for lithium storage. Pyridine N and quaternary N atoms can not fall off like pyrrole N atoms. 2. Co9S8/N-doped carbon nanosheet-based hollow sphere composite (Co9S8/NHCS) was prepared based on CoAl-LDH interlayer two-dimensional confinement effect, and its catalytic activity for oxygen reduction was studied. Firstly, m-aminobenzenesulfonate anion was inserted into CoAl-LDH by one-step hydrothermal method. Co9S8/NHCS was prepared by high temperature carbonization and selective acidification etching. The obtained Co9S8/NHCS has a hollow spherical structure consisting of a large number of nanosheets, in which monodisperse Co9S8 was implanted into carbon nanosheets. The structure has the following advantages: monodisperse Co9S8 particles were obtained based on the two-dimensional finite-region method, which prompted the formation of Co9S8 particles. The decomposition and carbonization of m-aminobenzenesulfonate anion and the formation of Co9S8 occur simultaneously, which makes the Co9S8 nanoparticles implanted into carbon nanosheets and thus has high stability. The hollow spherical structure of the precursor makes the prepared Co9S8/NHCS highly stable. In addition, the effects of calcination temperature and hollow spherical structure on the structure of the catalysts (such as specific surface area, pore distribution, nitrogen doping type, size and size of Co9S8) and The results showed that 900 C was the optimum calcination temperature and the hollow spherical structure played a very important role in enhancing the catalytic activity of ORR. Electrochemical tests showed that the CO9S8/NHCS catalysts prepared at 900 C had the highest ORR catalytic activity in both alkaline and acidic media, long-term stability and excellent anti-A activity. Alcohol toxicity. 3. Carbon nanosheet-based hollow sphere composites (Co-N/C) containing Co-Nx components were prepared based on the two-dimensional confinement effect of C oAl-LDH layers. The catalytic activity and active sites of the hollow sphere composites in different pH media were studied. The anions of m-aminobenzenesulfonate were firstly inserted into the layers of C oAl-LDH by one-step hydrothermal method and then recanalized. Co-N/C was prepared by carbonization and acidification etching at high temperatures. The obtained Co-N/C has a hollow spherical structure consisting of a large number of carbon nanosheets containing Co-Nx components, showing abundant mesopores and high specific surface area. As an ORR electrocatalyst, its catalytic activity in different pH media was tested. The electrochemical data showed that the Co-N/C had a hollow spherical structure at 900 C. The prepared C o-N/C catalyst exhibited the highest ORR activity, high half-wave potential and high limiting diffusion current in alkaline and neutral media. The performance of the catalyst was similar to that of commercial Pt/C catalyst, and showed excellent stability and anti-methanol toxicity. The ORR catalytic activity of Co-N/C catalyst before and after poisoning and the ORR catalytic activity of Co-N/C catalyst before and after destruction of Co-Nx site were compared. It was found that the catalytic activity of Co-N/C catalyst did not change significantly in alkaline medium, but in neutral and acidic medium, the catalytic activity of Co-N/C catalyst decreased significantly, indicating that the Co-N catalytic activity of Co-N/C catalyst decreased significantly. The x site acts as ORR active site directly in neutral and acidic media, but the effect on ORR catalytic activity is negligible under alkaline conditions. 4. Based on the two-dimensional confinement effect between CO(OH)2 layers, cobalt sulfide and nitrogen-doped carbon nano-flake-based flower composite (Co9S8/CO1-xS@) NC were prepared, and its formation mechanism and lithium storage properties were studied. Co9S8/Co1-xS@NC was prepared by mixing the intercalated Co(OH)2 precursor with sulfur powder and calcining it in N2 atmosphere. The obtained Co9S8/Co1-xS@NC consisted of a large number of nitrogen-doped carbon nanosheets embedded in small size cobalt sulfide nanoparticles. The intercalated Co (OH) 2 precursor was carbonized and vulcanized. It was found that the carbonization of m-Aminobenzene sulfonate ion to form carbon nanosheets occurred at about 200 ~400 ~C, accompanied by S sublimation and Co (OH) 2 layer. Co1-xS nanoparticles can be implanted in carbon nanosheets because of the decomposition and the formation of Co1-xS nanoparticles. With the increase of calcination temperature, some of Co1-xS is gradually transformed to Co9S8, and the graphitization degree of carbon nanosheets is further improved. Separation and relaxation of the volume stress produced in the process of lithium removal are helpful to improve the cyclic stability and rate performance of the electrode; nitrogen-doped carbon matrix and several layers of graphene coated on the outer surface of cobalt sulfide can not only prevent the aggregation of particles and reduce the resistance between particles, but also effectively alleviate the charge-discharge cycle process. The volume expansion of medium cobalt sulfide and the dissolution of polysulfide in electrolyte are helpful to improve the cyclic stability of the electrode; the thin particle-nanosheet structure can reduce the ion and electron transport distances, making the cobalt sulfide nanoparticles fully utilized, thus contributing to high specific capacity; the flower-like structure with large specific surface area The morphology and pore structure can promote the electrolyte to enter the electrode and accelerate the transfer of lithium ions. In addition, the composition of cobalt sulfide can be effectively controlled by changing the ratio of the precursor and sulfur powder or calcination temperature. As the anode material of lithium-ion batteries, the electrochemical tests show that the electrolyte is at 900 C and the mass ratio of the precursor and sulfur powder is 1:0.75. The prepared Co9S8/Co1-xS@NC exhibits high specific capacity and excellent rate performance. The method based on interlayer limiting synthesis of layered hydroxides proposed in this paper can be extended to prepare other functionally doped carbon-based nanomaterials with excellent properties, and can be used in supercapacitors, solar cells, sensors, environmental protection, catalysis and other fields. It has broad application prospects.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.1
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本文編號(hào)：2176984
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