氧化鎳、氧化釩微納結(jié)構(gòu)的控制及在儲能方面的研究
發(fā)布時間：2019-06-17 16:20
【摘要】：由于環(huán)境污染和能源危機(jī)問題日益突出,風(fēng)能、太陽能等產(chǎn)生的電能需要高效存儲,以及便攜式電子器件和電動汽車行業(yè)的快速發(fā)展,開發(fā)廉價、高效、環(huán)境友好、體積小和質(zhì)量輕的儲能裝置是各國研究者面臨的重要挑戰(zhàn)。像鋰離子電池和超級電容器這樣的儲能器件滿足上述各項要求,成為目前研究的熱點(diǎn)。而高性能的鋰離子電池和超級電容器的實(shí)現(xiàn)強(qiáng)烈依賴于電極材料的合理設(shè)計。其中,氧化鎳是一種贗電容機(jī)制的儲能材料,具有較高的理論比容量,在超級電容器領(lǐng)域被廣泛研究。而五氧化二釩作為一種鋰離子電池的正極材料,具有脫嵌鋰的存儲機(jī)制和高的能量密度,也是鋰離子電池電極材料近年來的研究熱點(diǎn)。這兩種材料都具有儲量豐富,價格低廉的共同優(yōu)點(diǎn)。但是作為過渡金屬氧化物,電導(dǎo)率低,循環(huán)穩(wěn)定性差的缺點(diǎn)限制了他們的廣泛應(yīng)用。研究發(fā)現(xiàn):如果將納米技術(shù)引入到電極材料的制備,對材料結(jié)構(gòu)進(jìn)行合理地設(shè)計,對于提高超級電容器和鋰離子電池的性能具有重要的意義。在本文中,我們旨在用簡單的方法合理設(shè)計和制備高性能超級電容器和鋰離子電池電極材料,為電極材料的發(fā)展提供有益的探索。本文的主要內(nèi)容如下:(1)采用水熱法合成了氫氧化鎳前軀體,通過調(diào)控溶液的ph值變化來調(diào)控不同形貌的前軀體。最后煅燒前軀體獲得了一系列不同形貌、不同比表面積和孔徑分布的蜂窩狀nio分級結(jié)構(gòu)。電化學(xué)測試結(jié)果證實(shí):nio電極表現(xiàn)出優(yōu)異的電容性能。在1ag-1的電流密度下,可提供1250fg-1的比容量;在5ag-1電流密度時,容量仍保持在945fg-1。當(dāng)循環(huán)3500圈后,容量保持率高達(dá)88.4%。該結(jié)構(gòu)之所以有較優(yōu)異的電容性能,與其高的比表面積,多的介孔含量以及大的孔容有較大關(guān)系。另外,將制備的nio作為電容器正極,用改進(jìn)的hummers法結(jié)合水熱還原法制備的rgo作為電容器負(fù)極,組裝成不對稱全電容。通過調(diào)節(jié)正負(fù)極材料質(zhì)量比例得到性能較好的全電容器器件。該器件可實(shí)現(xiàn)23.25whkg-1的能量密度及9.3kwkg-1的功率密度,并可成功點(diǎn)亮led燈。(2)通過溶劑熱法,合成了一系列不同形貌結(jié)構(gòu)(包括核殼結(jié)構(gòu)、雙壁結(jié)構(gòu)、三壁結(jié)構(gòu)和分級中空結(jié)構(gòu))的v2o5前軀體材料,并對不同形貌結(jié)構(gòu)材料的形成機(jī)理進(jìn)行了詳細(xì)的探討。電化學(xué)測試結(jié)果證實(shí):分級中空結(jié)構(gòu)v2o5具有優(yōu)異的電化學(xué)性能,在1c(147mag-1)電流密度下,2.5-4.0v電壓范圍內(nèi),可提供146.8mahg-1的比容量(理論比容量為147mahg-1)。當(dāng)電流密度為20c時,容量可達(dá)123mahg-1,循環(huán)3000圈后比容量仍能保持在73.5mahg-1。并且該材料在2.0-4.0v電壓范圍測試時同樣表現(xiàn)出優(yōu)良的循環(huán)穩(wěn)定性。另外,將其與商業(yè)化的li4ti5o12組裝成全電池,在1.0-2.5v的電壓范圍內(nèi),147mag-1的電流密度下,可提供最高139.5mahg-1的比容量;循環(huán)100圈后容量仍保持在106 mA g-1,其性能遠(yuǎn)遠(yuǎn)高于所報道的在相同測試條件下V2O5全電池性能。
[Abstract]:Due to the increasingly prominent problems of environmental pollution and energy crisis, the electric energy generated by wind energy and solar energy needs efficient storage, as well as the rapid development of portable electronic devices and electric vehicle industry. the development of cheap, efficient, environmentally friendly, small and light energy storage devices is an important challenge faced by researchers all over the world. Energy storage devices such as lithium-ion batteries and supercapacitors meet the above requirements and become the focus of current research. The realization of high performance lithium-ion batteries and supercapacitors depends strongly on the reasonable design of electrode materials. Among them, nickel oxide is a kind of energy storage material with pseudo-capacitance mechanism, which has high theoretical specific capacity and has been widely studied in the field of supercapacitors. Vanadium pentoxide, as a cathode material for lithium-ion batteries, has the storage mechanism of lithium removal and high energy density, and is also the research focus of lithium-ion battery electrode materials in recent years. These two materials have the common advantages of rich reserves and low price. However, as transition metal oxides, their wide application is limited by their low conductivity and poor cycle stability. It is found that if nanotechnology is introduced into the preparation of electrode materials and the structure of the materials is designed reasonably, it is of great significance to improve the performance of supercapacitors and lithium-ion batteries. In this paper, the purpose of this paper is to design and fabricate high performance supercapacitors and lithium ion battery electrode materials reasonably by simple method, and to provide useful exploration for the development of electrode materials. The main contents of this paper are as follows: (1) the precursor of nickel hydroxide was synthesized by hydrothermal method, and the precursor with different morphology was regulated by regulating the ph value of the solution. Finally, a series of honeycomb nio classification structures with different morphology, different surface area and pore size distribution were obtained. The electrochemical results show that the nio electrode has excellent capacitance performance. At the current density of 1ag-1, the specific capacity of 1250fg-1 can be provided, and at the current density of 5ag-1, the capacity can still be kept at 945fg 鈮，
本文編號：2501114
[Abstract]:Due to the increasingly prominent problems of environmental pollution and energy crisis, the electric energy generated by wind energy and solar energy needs efficient storage, as well as the rapid development of portable electronic devices and electric vehicle industry. the development of cheap, efficient, environmentally friendly, small and light energy storage devices is an important challenge faced by researchers all over the world. Energy storage devices such as lithium-ion batteries and supercapacitors meet the above requirements and become the focus of current research. The realization of high performance lithium-ion batteries and supercapacitors depends strongly on the reasonable design of electrode materials. Among them, nickel oxide is a kind of energy storage material with pseudo-capacitance mechanism, which has high theoretical specific capacity and has been widely studied in the field of supercapacitors. Vanadium pentoxide, as a cathode material for lithium-ion batteries, has the storage mechanism of lithium removal and high energy density, and is also the research focus of lithium-ion battery electrode materials in recent years. These two materials have the common advantages of rich reserves and low price. However, as transition metal oxides, their wide application is limited by their low conductivity and poor cycle stability. It is found that if nanotechnology is introduced into the preparation of electrode materials and the structure of the materials is designed reasonably, it is of great significance to improve the performance of supercapacitors and lithium-ion batteries. In this paper, the purpose of this paper is to design and fabricate high performance supercapacitors and lithium ion battery electrode materials reasonably by simple method, and to provide useful exploration for the development of electrode materials. The main contents of this paper are as follows: (1) the precursor of nickel hydroxide was synthesized by hydrothermal method, and the precursor with different morphology was regulated by regulating the ph value of the solution. Finally, a series of honeycomb nio classification structures with different morphology, different surface area and pore size distribution were obtained. The electrochemical results show that the nio electrode has excellent capacitance performance. At the current density of 1ag-1, the specific capacity of 1250fg-1 can be provided, and at the current density of 5ag-1, the capacity can still be kept at 945fg 鈮，
本文編號：2501114
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