锂—空气电池负极材料锂的掺杂改性研究

发布时间：2018-04-11 20:40

本文选题：钠掺杂 + 钾掺杂　；参考：《合肥工业大学》2017年硕士论文

【摘要】：本论文将制备的钠掺杂的Li_(1-x)Nax(x = 0.02, 0.03, 0.06, 0.10)和钾掺杂的Li_(1-x)Kx(x = 0.01,0.015, 0.02)负极材料用于锂-空气电池负极,以改善其电化学性能。并通过XRD,FESEM等技术表征手段研究所制备负极材料的晶型结构、形貌和表面组成。通过组装有机系锂-空气电池测试样品的性能。并使用恒流充放电测试、交流阻抗测试(EIS)以及循环伏安测试(CV)来分析电池的循环稳定性、循环寿命以及其内部反应机理。以20% Pt/C为催化剂,以Li_(1-x)Nax(x = 0.02, 0.03, 0.06)和商用锂分别为有机锂-空气电池负极材料,研究其电池性能。在电流密度为100mAg-1的条件下首次充-放电时,Li_(1-x)Nax(x = 0.03)展现出了最好的电化学性能,且具有最低的过电压(0.8V)。当电流密度为200mA g-1且限制充放电容量为500mA h g-1时,Li_(1-x)Nax(x = 0.03)也表现出了超高的循环寿命(230次)。当电流密度在50 mA g-1到500 mA g-1范围内放电时,Li_(1-x)Nax(x = 0.03)较纯锂也表现出了较好的倍率性能。同样以20%pt/c为催化剂,以Li_(1-x)kx(x=0.0,0.01,0.015,0.02)为负极时,在电流密度为100 mA g-1的条件下,Li_(1-x)kx(x = 0.0, 0.01,0.015,0.02)的首次放电容量分别为 3291 mA h·g-1,3439 mAh g-1,3537 mAh g-1 和 2468 mAh g-1,当电流密度为250mAg-1时,分别截止充放电容量为500mAhg-和1000 mAhg-1时,Li_(1-x)kx(x = 0.015)均具有较好的循环性能,但仍然有待提高。为设计成本低且容量高的电池,采用价格低廉的KB为催化剂,研究Li_(1-x)Nax(x = 0.02, 0.06, 0.10)样品为锂-空气电池负极时的性能。在100 mAg-1的电流密度下首次充放电时,Li_(1-x)Nax(x=0.06)样品具有超高的放电容量(11488 mAh g-1)且远高于其它负极材料。在电流密度为250 mAg-1,截止容量为500 mAh g-1的条件下,Li_(1-x)Nax(x=0.06)表现出最好的循环性能。但当截止容量提高至1000mAhg-1,与纯锂相比,Li_(1-x)Nax(x = 0.06)循环性能有所改善但不明显。
[Abstract]:In this paper, Li_(1-x)Nax(x = 0.02,0.03,0.06,0.10) and Li_(1-x)Kx(x = 0.01n 0.015, 0.02) were prepared to improve the electrochemical performance of lithium-air batteries.The crystal structure, morphology and surface composition of negative electrode materials were prepared by means of XRD- FESEM and other techniques.The performance of the samples was tested by assembling organic lithium-air batteries.The constant current charge-discharge test, AC impedance test (EIS) and cyclic voltammetry test (CVV) were used to analyze the cycle stability, cycle life and internal reaction mechanism of the battery.Using 20% Pt/C as catalyst, Li_(1-x)Nax(x = 0.02, 0.03, 0.06) and commercial lithium as anode materials for organic lithium-air batteries, the battery performance was studied.At the condition of current density of 100mAg-1, the first charge-discharge process shows the best electrochemical performance, and the lowest overvoltage is 0.8 V ~ (-1).When the current density is 200mA g ~ (-1) and the limited charge / discharge capacity is 500mA h ~ (g ~ (-1)), the number of cycles is 230times when the current density is 200mA g ~ (-1) and the current density is 200mA g ~ (-1) and the limit capacity of charge / discharge is 500mA h / g ~ (-1).When the current density is in the range of 50 Ma g ~ (-1) to 500 Ma g ~ (-1), Li-Li _ (1-x) Naxo _ x = 0.03) also shows better rate performance than pure lithium.The cutoff charge-discharge capacities of 500mAhg- and 1000 mAhg-1 respectively have good cycling performance, but still need to be improved.In order to design a battery with low cost and high capacity, the performance of lithium air battery with Li_(1-x)Nax(x = 0.02, 0.06, 0.10) was studied by using low cost KB as catalyst.When charged and discharged for the first time at a current density of 100 mAg-1, the sample has a superhigh discharge capacity of 11488 mAh g ~ (-1) and is much higher than that of other anode materials.When the current density is 250mAg-1 and the cutoff capacity is 500 mAh g ~ (-1), the best cycling performance is obtained.However, when the cutoff capacity is increased to 1000mAhg-1, compared with pure lithium, the cycle performance of LiLiAZ 1-xNax-X = 0.06) is improved but not obvious.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM911.41;TQ131.11

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