本文選題：二次電池 + 鋰-氧氣電池�。� 參考：《南京大學(xué)》2017年碩士論文

【摘要】：環(huán)境污染和能源短缺制約人類的可持續(xù)發(fā)展。為此,大力發(fā)展清潔可再生能源,已經(jīng)成為人類社會(huì)的共識(shí)。清潔能源的存儲(chǔ)和利用要求性能良好的能量存儲(chǔ)轉(zhuǎn)化設(shè)備。鋰-離子電池自上世紀(jì)末問世以來,在移動(dòng)便攜設(shè)備領(lǐng)域取得了極大的成功。但是,由于其活性物質(zhì)固有化學(xué)性質(zhì)的限制,鋰-離子電池有限的能量密度難以滿足長(zhǎng)距離續(xù)航里程電動(dòng)汽車的要求。鋰-氧氣電池利用大氣中的氧氣和金屬鋰參與反應(yīng),具有可與以汽油為燃料的內(nèi)燃機(jī)相媲美的理論能量密度。然而,金屬鋰負(fù)極受制于鋰枝晶生長(zhǎng)和低庫(kù)倫效率的問題,目前還難以在獲得實(shí)際應(yīng)用。針對(duì)這一問題,研究者提出使用合金負(fù)極材料以取代金屬鋰負(fù)極,從而構(gòu)建鋰離子-氧氣電池的設(shè)想。硅基材料由于其較高的理論比容量和較低的工作電位,被認(rèn)為是鋰離子-氧氣電池的一個(gè)合適選擇。本文基于硅基合金負(fù)極材料,對(duì)鋰離子-氧氣電池進(jìn)行了設(shè)計(jì)和組裝,并通過XRD、SEM、TGA、XPS以及充放電測(cè)試等分析方法,探究了非鋰負(fù)極鋰離子-氧氣電池的電化學(xué)性能及充放電反應(yīng)過程。我們首先合成了兩種基于多壁碳納米管的復(fù)合催化劑材料,用于鋰離子-氧氣電池的正極。在鉑修飾多壁碳納米管材料中,少量金屬鉑納米顆粒均勻生長(zhǎng)在多壁碳納米管管壁上;在核殼結(jié)構(gòu)二氧化釕多壁碳納米管材料中,大量二氧化釕晶體包覆在多壁碳納米管外,形成了核殼結(jié)構(gòu)。鉑修飾多壁碳納米管復(fù)合材料作正極的鋰-氧氣電池在定容量充放電條件下能夠穩(wěn)定循環(huán)100圈。核殼結(jié)構(gòu)二氧化釕多壁碳納米管復(fù)合材料作正極的鋰-氧氣電池可以有效降低充電過電位。并且可以在較大電流密度下實(shí)現(xiàn)了穩(wěn)定全充放循環(huán)。通過對(duì)鉑修飾多壁碳納米管的充放電產(chǎn)物進(jìn)行表征,證明電池的放電充電過程基于Li2O2晶體的可逆生長(zhǎng)和分解。由于硅基材料不含鋰,不能直接作為鋰離子-氧氣電池的負(fù)極材料,我們通過高能球磨法制備了鋰硅合金負(fù)極材料。鋰硅合金主要成分為L(zhǎng)i21Si5,且顆粒尺寸分布在1 μm到5 μm。電化學(xué)性能測(cè)試表明鋰硅合金首圈脫鋰比容量為1118 mAh·g-1。鋰硅合金在大電流條件下50圈充放電循環(huán)后依然保持了 571 mAh·g-1的可逆容量,同時(shí),庫(kù)倫效率穩(wěn)定在98.5%左右。使用鋰硅合金負(fù)極和鉑修飾多壁碳納米管正極組裝鋰離子-氧氣電池,在500 mA·g-1的電流密度下可以穩(wěn)定循環(huán)80圈。同時(shí)我們還對(duì)不同正負(fù)極質(zhì)量配比的鋰離子-氧氣電池的循環(huán)穩(wěn)定性進(jìn)行了研究。通過對(duì)比循環(huán)前后的鋰硅合金電極,我們發(fā)現(xiàn)鋰硅合金在循環(huán)過程中逐漸轉(zhuǎn)化為無定形態(tài)。同時(shí),循環(huán)過程中生成了 LiOH以及少量醚類物質(zhì)等副產(chǎn)物。我們認(rèn)為這造成了鋰硅合金材料在循環(huán)過程中的不穩(wěn)定。我們還設(shè)計(jì)并組裝了一種新型鋁塑膜軟包裝鋰離子-氧氣電池,通過預(yù)裝金屬鋰源對(duì)硅電極進(jìn)行電化學(xué)鋰化。使用基于海藻酸鈉粘結(jié)劑涂膜的納米硅電極作為鋰離子-氧氣電池負(fù)極,其首圈放電比容量為3087.8 mAh·g-1。在0.25 C的電流密度下穩(wěn)定循環(huán)200圈,可逆比容量達(dá)到1500.2 mAh·g-1,容量保持率高達(dá)75.4%。組裝軟包電池后,通過反復(fù)的放電與靜置操作,對(duì)硅電極進(jìn)行電化學(xué)鋰化,該體系下生成的鋰硅合金成分主要為L(zhǎng)i21Si8。以此為基礎(chǔ)進(jìn)行鋰離子-氧氣電池的測(cè)試,電池放電比容量為343.1 mAh·g-1,且?guī)靷愋蔬_(dá)到100%。該方法在既可以實(shí)現(xiàn)電化學(xué)方法鋰化硅電極,同時(shí)又避免了電池反復(fù)拆解組裝帶來的問題。通過上述幾個(gè)方面,我們對(duì)不同結(jié)構(gòu)的基于鋰硅合金負(fù)極的鋰離子-氧氣電池進(jìn)行了初步的研究。這將為未來鋰離子-氧氣電池的結(jié)構(gòu)設(shè)計(jì)和性能優(yōu)化提供新的思路。
[Abstract]:Environmental pollution and energy shortage restrict the sustainable development of human beings. To this end, the development of clean and renewable energy has become a common understanding of human society. The storage and utilization of clean energy requires good performance of energy storage conversion equipment. Lithium ion batteries have come from the end of last century and have made a great deal in the field of mobile portable equipment. However, due to the inherent chemical properties of its active substance, the limited energy density of lithium ion batteries is difficult to meet the requirements of a long range mileage electric vehicle. The lithium oxygen battery takes part in the reaction with the oxygen and metal lithium in the atmosphere, and has a theoretical energy density comparable to that of gasoline as a combustion engine. The metal lithium anode is subject to the problem of lithium dendrite growth and low Kulun efficiency, and it is still difficult to get practical application at present. In view of this problem, the researchers have proposed the use of alloy negative electrode to replace the metal lithium anode to construct the lithium ion oxygen battery. The silicon base material is from its higher theoretical specific capacity and lower working power. It is considered to be a suitable choice for lithium ion oxygen batteries. Based on the silicon based alloy negative electrode, the lithium ion oxygen battery was designed and assembled. The electrochemical performance and charge discharge reaction process of the non lithium negative lithium ion oxygen battery were investigated by means of XRD, SEM, TGA, XPS and charge discharge test. We first synthesized two kinds of composite catalysts based on multi walled carbon nanotubes for the cathode of the lithium ion oxygen battery. In the platinum modified multi walled carbon nanotubes, a small amount of platinum nanoparticles grow evenly on the wall of the multi wall carbon nanotube. In the nuclear shell structure two ruthenium oxide multi wall carbon nanotube materials, a large number of ruthenium oxide crystals are found. The body is coated with multi wall carbon nanotubes, forming a nuclear shell structure. The lithium oxygen battery with platinum modified multi wall carbon nanotube composite material can stabilize 100 cycles under the constant capacity charge and discharge condition. The lithium oxygen gas battery of the nuclear shell structure two ruthenium oxide multi wall carbon nanotube composite material can effectively reduce the charge overpotential. The charge discharge product of the platinum modified multi wall carbon nanotubes is characterized by the characterization of the charge and discharge products of the platinum modified multi wall carbon nanotubes. It is proved that the discharge charging process of the battery is based on the reversible growth and decomposition of the Li2O2 crystal. Lithium silicon alloy negative electrode is prepared by ball milling. The main component of lithium silicon alloy is Li21Si5, and the particle size distribution from 1 to 5 m. shows that the lithium silicon alloy first coil stripping ratio is 1118 mAh. G-1. lithium silicon alloy still maintains the reversible capacity of 571 mAh. G-1 after 50 ring charge discharge cycle under large current condition. At the same time, the efficiency of Kulun is stable at about 98.5%. Lithium ion oxygen battery is assembled with lithium silicon alloy negative electrode and platinum modified multi wall carbon nanotube cathode. The cycle of 80 cycles can be stabilized under the current density of 500 mA. G-1. The cycle stability of lithium ion oxygen batteries with different positive and negative mass ratio is also studied. Compared with the lithium silicon alloy electrode before and after the cycle, we found that the lithium silicon alloy was gradually transformed into an amorphous form during the cycle process. At the same time, LiOH and a small amount of other products were produced during the cycle process. We think this resulted in the instability of the lithium silicon alloy during the cycle process. The plastic film soft packaging lithium ion oxygen battery is electrochemical lithium ion by preloading the metal lithium source. The nano silicon electrode based on sodium alginate adhesive coating is used as the anode of the lithium ion oxygen battery. The discharge ratio of the first coil is 200 cycles at the current density of 3087.8 mAh. G-1. at 0.25 C, and the reversible specific capacity reaches 1. After 500.2 mAh. G-1, the capacity retention rate is up to 75.4%. package battery, the silicon electrode is electrochemical lithium by repeated discharge and static operation. The composition of the lithium silicon alloy under this system is mainly Li21Si8. on the basis of the lithium ion oxygen battery test. The battery discharge specific capacity is 343.1 mAh. G-1 and Kulun efficiency. To achieve 100%., this method can not only realize the electrochemical method of lithium silicon electrode, but also avoid the problems caused by repeated disassembly and assembly of the battery. Through the above several aspects, we have studied the lithium ion oxygen battery based on the lithium silicon alloy anode of different structures. This will be the structure of the lithium ion oxygen battery in the future. New ideas are provided for planning and performance optimization.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM911.41
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本文編號(hào)：2065684