本文選題：鋰離子電池 + Cu_2V_2O_7�。� 參考：《陜西科技大學(xué)》2017年碩士論文

【摘要】：眾多清潔能源的推廣應(yīng)用對(duì)新一代儲(chǔ)能系統(tǒng)提出更高的要求。鋰離子電池憑借其眾多優(yōu)勢(shì),成為大型儲(chǔ)能系統(tǒng)的首選設(shè)備之一。目前制約鋰離子電池發(fā)展的關(guān)鍵因素就是其電極材料容量較低,無(wú)法滿足現(xiàn)實(shí)需求。具有層狀結(jié)構(gòu)和多步還原特性的釩酸銅材料,在諸多領(lǐng)域均顯示出優(yōu)異的性能,具有廣泛的應(yīng)用前景。但目前對(duì)其電化學(xué)性能的研究還處于初步階段。本論文通過(guò)不同方法,通過(guò)調(diào)控工藝參數(shù)制備出不同物相及形貌的釩酸銅材料,采用X射線衍射、掃描電鏡等表征方法以及恒流充放電設(shè)備、循環(huán)伏安曲線和阻抗測(cè)試等研究了制備工藝對(duì)材料組成、結(jié)構(gòu)和電化學(xué)性能的影響。采用固相法制備出不同物相的釩酸銅材料,探究不同煅燒溫度,保溫時(shí)間及原料配比對(duì)產(chǎn)物的物相、形貌及電化學(xué)性能的影響。發(fā)現(xiàn)提高煅燒溫度,產(chǎn)物的結(jié)晶性和粒徑尺寸逐漸增加,產(chǎn)物物相從α相變?yōu)棣孪唷．a(chǎn)物形貌也發(fā)生了從不規(guī)則顆粒狀逐漸生長(zhǎng)為珊瑚狀,再到不規(guī)則塊狀的變化。當(dāng)銅釩物質(zhì)的量之比為1:1,600 ℃保溫2h,可制備出珊瑚狀α-Cu2V2O7材料。在50mA·g-1條件下,其可逆容量為370mAh·g-1。以氧化亞銅代替氧化銅作為銅源,可大幅度縮短反應(yīng)所需的時(shí)間,降低反應(yīng)溫度。以氧化亞銅為銅源及模板,采用水浴法制備出三維花狀Cu3V2O7(OH)2·2H2O材料。通過(guò)調(diào)節(jié)溫度及pH,可實(shí)現(xiàn)對(duì)產(chǎn)物形貌和物相的控制。發(fā)現(xiàn)相對(duì)于純相 Cu3V2O7(OH)2·2H2O,Cu3V2O7(OH)2·2H2O/Cu2O復(fù)合材料具有更優(yōu)異的電化學(xué)性能。其中,pH為7.41,在70℃水浴反應(yīng)5 h制得的花狀樣品,在100 mA·g-1電流密度下,其首次放電比容量為941.3 mAh·g-1,100圈循環(huán)后容量為414.7 mAh g-1。采用水熱法結(jié)合后續(xù)熱處理,在較低的溫度下合成出具有介孔結(jié)構(gòu)的球狀Cu2V2O7/rGO復(fù)合材料。研究了反應(yīng)溫度、時(shí)間以及還原氧化石墨烯的加入量對(duì)產(chǎn)物物相及性能的影響。60℃下反應(yīng)20 h,復(fù)合0.6%還原氧化石墨烯,經(jīng)熱處理所得材料具有較好的電化學(xué)性能,在100mA·g-1電流密度下,其首次放電比容量為1245 mAh·g-1,100圈循環(huán)之后,容量可保持在 900 mAh·g-1。在 100、200、500、1000、2000、5000 mA·g-1 的電流密度下比容量分別為890、817、690、524、328、170 mAh·g-1,其性能明顯優(yōu)于純相Cu2V207。適量還原氧化石墨烯的加入,可提升材料的電化學(xué)性能,其與Cu2V207之間具有協(xié)同儲(chǔ)能效應(yīng)。
[Abstract]:The popularization and application of many clean energy sources put forward higher requirements for the new generation energy storage system. Lithium ion battery has become one of the first choice equipment of large energy storage system with its many advantages. The key factor restricting the development of lithium-ion battery is that its electrode material capacity is low, which can not meet the actual demand. Copper vanadate with layered structure and multi-step reduction has shown excellent properties in many fields and has a wide application prospect. However, the study of its electrochemical performance is still in its preliminary stage. In this paper, copper vanadate materials with different phases and morphologies were prepared by adjusting the process parameters by different methods. The materials were characterized by X-ray diffraction, scanning electron microscopy and constant current charging and discharging equipment. The effects of preparation process on the composition, structure and electrochemical properties of the materials were investigated by cyclic voltammetry and impedance measurements. Copper vanadate with different phases was prepared by solid phase method. The effects of different calcination temperature, holding time and ratio of raw materials on the phase, morphology and electrochemical properties of the products were investigated. It was found that the crystallinity and particle size of the product increased gradually with the increase of calcination temperature, and the phase transition from 偽 to 尾 phase was observed. The morphology of the product also changed from irregular granular to coral and then irregular block. Coral-like 偽 -Cu _ 2V _ 2O _ 7 can be prepared when the ratio of copper and vanadium is 1: 1600 鈩，

本文編號(hào)：1934390