基于三維多孔鎳沉積二氧化錳電極電化學(xué)特性的研究
發(fā)布時間：2019-05-07 09:24
【摘要】：面對資源急劇的消耗,人類亟待在能源利用與環(huán)境污染間尋得平衡,新型儲能材料成為世界各國的研究重點。電化學(xué)電容器作為新型儲能材料,能量密度大、充放電速率高,優(yōu)勢明顯。其中,二氧化錳具有較高的理論比容量(SC)1370 F g-1,成本低廉對環(huán)境友好,常作為電化學(xué)電容器電極材料。但是,二氧化錳導(dǎo)電性差,高比容量只存在于二氧化錳膜層較薄的情況下,因而制備具有大比表面和超薄膜層的二氧化錳是獲得高比容量的有效途徑。本文在三維多孔鎳上陽極電沉積二氧化錳,并改變沉積參數(shù)控制其微觀形貌的變化,深入討論了二氧化錳/多孔鎳電極的沉積參數(shù)、形貌和電化學(xué)性能之間的關(guān)系,探索了制備高性能電化學(xué)電容器電極材料的有效途徑。本文首先通過恒電流法沉積二氧化錳,分別改變沉積電流密度和沉積時間,并對多孔鎳沉積二氧化錳的形貌進行分析,實驗結(jié)果表明:隨著沉積電流密度增大,多孔鎳鎳柱上沉積的氧化錳形態(tài)由纖維狀向均勻包裹鎳柱的連續(xù)涂層轉(zhuǎn)變。電極性能與沉積電流密度和循環(huán)伏安掃描速率的大小以及沉積物形貌關(guān)系密切。沉積電流密度為10 m A cm-2、沉積時間為10 min的多孔鎳二氧化錳電極面積比電容值在1 m V s-1的掃描速率下達到0.9 F cm-2,其體積比電容值為200 F cm-3;在掃描速率為10 m V s-1時,面積比電容在經(jīng)過1000個循環(huán)后僅僅由0.528 F cm-2下降為0.525 F cm-2,具有良好的循環(huán)穩(wěn)定性。隨后,本論文在恒定電量條件下恒壓沉積二氧化錳,改變沉積電壓和沉積溫度,研究沉積參數(shù)對二氧化錳微觀形貌的影響,并討論了形貌與二氧化錳/多孔鎳復(fù)合電極電化學(xué)性能的關(guān)系。實驗結(jié)果表明:隨著沉積電壓的下降,晶粒成核速率隨之降低,氧化錳沉積物形貌由納米顆粒轉(zhuǎn)化為納米纖維;而隨著沉積溫度的上升,晶粒生長速率逐漸超越成核速率,氧化錳沉積物形貌出現(xiàn)類似的變化規(guī)律,由納米顆粒轉(zhuǎn)變?yōu)榧{米纖維簇。其中,納米片(花瓣)狀,納米串珠,納米顆粒/柱分別為顆粒轉(zhuǎn)變?yōu)槔w維的過渡態(tài),其形貌是由成核速率的大小以及晶體生長過程中生長速率和成核速率的關(guān)系共同作用的結(jié)果。同等電量(Q=1.8 C)沉積下,面積比電容值最大時的沉積條件為:沉積溫度0°C,沉積電壓0.75 V,此時樣品面積比電容值為0.311 F cm-2(掃描速率10 m V s-1),形貌為納米串珠狀。
[Abstract]:In the face of the rapid consumption of resources, human beings need to find a balance between energy use and environmental pollution, and new energy storage materials have become the focus of research all over the world. As a new type of energy storage material, electrochemical capacitor has high energy density, high charge-discharge rate and obvious advantages. Manganese dioxide (MNO _ 2) has high theoretical specific capacity (SC) 1370 F / g ~ (1), low cost and environmental friendliness, and is often used as electrode material for electrochemical capacitors. However, the conductivity of manganese dioxide is poor, and the high specific capacity only exists in the case of thin manganese dioxide film. Therefore, the preparation of manganese dioxide with large specific surface area and ultra-thin film is an effective way to obtain high specific capacity. In this paper, manganese dioxide was electrodeposited on three-dimensional porous nickel anode, and the change of micro-morphology was controlled by changing the deposition parameters. The relationship between deposition parameters, morphology and electrochemical properties of manganese dioxide / porous nickel electrode was discussed in depth. An effective way to fabricate electrode materials for electrochemical capacitors with high performance has been explored. In this paper, firstly, manganese dioxide was deposited by constant current method, the deposition current density and deposition time were changed, and the morphology of manganese dioxide deposited by porous nickel was analyzed. The experimental results show that: with the increase of deposition current density, The morphology of manganese oxide deposited on porous Ni-Ni column changed from fiber-like to continuous coating coated uniformly. The electrode performance is closely related to the deposition current density, cyclic voltammetry scanning rate and sediment morphology. When the deposition current density is 10 Ma cm-2, and the deposition time is 10 min, the specific capacitance of porous nickel manganese dioxide electrode reaches 0.9 F / cm-2, at the scanning rate of 1 MV / s / 1, and the volume specific capacitance is 200 F / cm-3;. At a scanning rate of 10 MV 路s ~ (- 1), the area specific capacitance only decreases from 0.528 F cm-2 to 0.525 F / cm-2, after 1000 cycles and has good cycling stability. In this paper, the deposition voltage and temperature of manganese dioxide were changed, and the effect of deposition parameters on the microstructure of manganese dioxide was studied. The relationship between morphology and electrochemical performance of manganese dioxide / porous nickel composite electrode was also discussed. The experimental results show that with the decrease of deposition voltage, the nucleation rate of grains decreases, and the morphology of manganese oxide deposits is transformed from nano-particles to nano-fibers. With the increase of deposition temperature, the grain growth rate gradually exceeded the nucleation rate, and the morphology of manganese oxide deposits changed from nano-particles to nano-fiber clusters. Among them, nano-slice (petal)-like, nano-bead, nano-particle / column is the transition state of the particle to the fiber, respectively. The morphology is affected by the size of nucleation rate and the relationship between growth rate and nucleation rate during crystal growth. The deposition conditions are as follows: deposition temperature 0 擄C, deposition voltage 0.75 V, sample area specific capacitance 0.311 F / cm-2 (scanning rate 10 MV / s / 1), when the area specific capacitance is maximum at the same amount of electricity (Q = 1.8 C), the deposition temperature is 0 擄C, the deposition voltage is 0.75 V, and the specific capacitance of the sample is 0.311 F / V. The morphology is nano-string beads.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TM53
本文編號：2470966
[Abstract]:In the face of the rapid consumption of resources, human beings need to find a balance between energy use and environmental pollution, and new energy storage materials have become the focus of research all over the world. As a new type of energy storage material, electrochemical capacitor has high energy density, high charge-discharge rate and obvious advantages. Manganese dioxide (MNO _ 2) has high theoretical specific capacity (SC) 1370 F / g ~ (1), low cost and environmental friendliness, and is often used as electrode material for electrochemical capacitors. However, the conductivity of manganese dioxide is poor, and the high specific capacity only exists in the case of thin manganese dioxide film. Therefore, the preparation of manganese dioxide with large specific surface area and ultra-thin film is an effective way to obtain high specific capacity. In this paper, manganese dioxide was electrodeposited on three-dimensional porous nickel anode, and the change of micro-morphology was controlled by changing the deposition parameters. The relationship between deposition parameters, morphology and electrochemical properties of manganese dioxide / porous nickel electrode was discussed in depth. An effective way to fabricate electrode materials for electrochemical capacitors with high performance has been explored. In this paper, firstly, manganese dioxide was deposited by constant current method, the deposition current density and deposition time were changed, and the morphology of manganese dioxide deposited by porous nickel was analyzed. The experimental results show that: with the increase of deposition current density, The morphology of manganese oxide deposited on porous Ni-Ni column changed from fiber-like to continuous coating coated uniformly. The electrode performance is closely related to the deposition current density, cyclic voltammetry scanning rate and sediment morphology. When the deposition current density is 10 Ma cm-2, and the deposition time is 10 min, the specific capacitance of porous nickel manganese dioxide electrode reaches 0.9 F / cm-2, at the scanning rate of 1 MV / s / 1, and the volume specific capacitance is 200 F / cm-3;. At a scanning rate of 10 MV 路s ~ (- 1), the area specific capacitance only decreases from 0.528 F cm-2 to 0.525 F / cm-2, after 1000 cycles and has good cycling stability. In this paper, the deposition voltage and temperature of manganese dioxide were changed, and the effect of deposition parameters on the microstructure of manganese dioxide was studied. The relationship between morphology and electrochemical performance of manganese dioxide / porous nickel composite electrode was also discussed. The experimental results show that with the decrease of deposition voltage, the nucleation rate of grains decreases, and the morphology of manganese oxide deposits is transformed from nano-particles to nano-fibers. With the increase of deposition temperature, the grain growth rate gradually exceeded the nucleation rate, and the morphology of manganese oxide deposits changed from nano-particles to nano-fiber clusters. Among them, nano-slice (petal)-like, nano-bead, nano-particle / column is the transition state of the particle to the fiber, respectively. The morphology is affected by the size of nucleation rate and the relationship between growth rate and nucleation rate during crystal growth. The deposition conditions are as follows: deposition temperature 0 擄C, deposition voltage 0.75 V, sample area specific capacitance 0.311 F / cm-2 (scanning rate 10 MV / s / 1), when the area specific capacitance is maximum at the same amount of electricity (Q = 1.8 C), the deposition temperature is 0 擄C, the deposition voltage is 0.75 V, and the specific capacitance of the sample is 0.311 F / V. The morphology is nano-string beads.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TM53
【參考文獻】
相關(guān)碩士學(xué)位論文 前1條
1 崔德源;二氧化錳電極材料制備與性能研究[D];大連理工大學(xué);2011年
，本文編號：2470966
本文鏈接：http://sikaile.net/kejilunwen/dianlilw/2470966.html
最近更新
教材專著
