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Na0.44MnO2在碱性溶液中的电化学机制 被引量:7
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作者 李慧 刘双宇 +8 位作者 袁天赐 王博 盛鹏 徐丽 赵广耀 白会涛 陈新 陈重学 曹余良 《物理化学学报》 SCIE CAS CSCD 北大核心 2020年第5期114-120,共7页
Na0.44MnO2具有原料丰富、合成简单、无毒环境友好、结构稳定性高等优势,适合作为水溶液钠离子电池的正极材料。Na0.44MnO2在中性水溶液中的比容量较低(30–40 mAh·g^−1),而采用碱性电解液可大大提高Na0.44MnO2的可逆比容量(80 mAh... Na0.44MnO2具有原料丰富、合成简单、无毒环境友好、结构稳定性高等优势,适合作为水溶液钠离子电池的正极材料。Na0.44MnO2在中性水溶液中的比容量较低(30–40 mAh·g^−1),而采用碱性电解液可大大提高Na0.44MnO2的可逆比容量(80 mAh·g^−1)。当我们扩宽碱性电池的充放电窗口(1.95–0.3 V)时,在1.0 V(vs Zn/Zn^2+)附近出现一个宽的放电平台,且首周放电比容量高达275 mAh·g^−1,远远超出其理论嵌钠容量(121 mAh·g^−1)。本文我们通过对不同放电深度下的电极进行X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)和电感耦合等离子体发射光谱(ICP-AES)表征,研究其超额容量的放电机理。结果表明1.0 V以下的低电位放电过程可分为两个阶段:第一阶段为H+在隧道结构中的嵌入,此时隧道结构保持不变,放电曲线上表现为平台区;第二阶段为过量H+的嵌入引起隧道结构破坏,同时伴随着Mn(OH)2相的生成和Na+从结构中释放出来,放电曲线上表现为斜坡区。这一研究结果表明Na0.44MnO2在碱液中的可逆性与下限电位紧密相关,高稳定的Na0.44MnO2材料需要避免H+的嵌入。 展开更多
关键词 钠离子电池 Na0.44MnO2 碱性电解液 电化学机制 质子嵌入
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NaOH浓度对Na_(0.44)MnO_(2)储钠性能的影响 被引量:1
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作者 李慧 刘双宇 +8 位作者 袁天赐 王博 盛鹏 徐丽 赵广耀 白会涛 陈新 陈重学 曹余良 《物理化学学报》 SCIE CAS CSCD 北大核心 2021年第3期73-79,共7页
我们通过球磨法及后续的高温焙烧合成出了短棒状的Na_(0.44)MnO_(2),并研究了其作为碱性水溶液钠离子电池正极时,电解液NaOH浓度对其电化学性能的影响。结果表明,提高NaOH浓度有利于抑制嵌氢反应的发生并改善电极的循环性能和倍率性能,... 我们通过球磨法及后续的高温焙烧合成出了短棒状的Na_(0.44)MnO_(2),并研究了其作为碱性水溶液钠离子电池正极时,电解液NaOH浓度对其电化学性能的影响。结果表明,提高NaOH浓度有利于抑制嵌氢反应的发生并改善电极的循环性能和倍率性能,但同时也会造成析氧反应的提前触发,浓度过高时则又会降低其倍率性能。Na_(0.44)MnO_(2)在8 mol·L^(−1) NaOH中表现出了最佳的电化学性能,0.5C(1C=121 mA·g^(−1))的电流密度下,比容量达到79.2 mAh·g^(−1),50C时,仍能释放出35.3 mAh·g^(−1)的比容量,在0.2–1.2 V(vs.NHE)的电压窗口内,500周后容量保持率64.3%。此外,我们也发现缩小电压窗口可以减少副反应、改善循环性能。Na_(0.44)MnO_(2)在浓碱电解液中也表现出了优异的耐过充能力。上述结果不仅表明通过优化电解液体系和测试条件可大大改善Na_(0.44)MnO_(2)的储钠性能,同时也证实了Na_(0.44)MnO_(2)作为一种水溶液钠离子电池正极材料,在大规模储能领域具有良好的应用前景。 展开更多
关键词 钠离子电池 Na_(0.44)MnO_(2) 电化学性能 浓度 过充
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Facile Li-Al layered double hydroxide films on Al alloy for enhanced hydrophobicity, anti-biofouling and anti-corrosion performance 被引量:2
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作者 Ji Li tianci yuan +7 位作者 Chengliang Zhou Bo Chen Yi Shuai Dawang Wu Dongchu Chen Xiaohu Luo Y.Frank Cheng Yali Liu 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第20期230-242,共13页
In this work,lithium(Li)-aluminum(Al)layered double hydroxide(LDH)films modified by 4-amino-2-((hydrazine methylene)amino)-4-oxobutanoic acid(denoted as AOA acid)and/or 1H,1H,2H,2H-perfluorooctyltriethoxysilane were p... In this work,lithium(Li)-aluminum(Al)layered double hydroxide(LDH)films modified by 4-amino-2-((hydrazine methylene)amino)-4-oxobutanoic acid(denoted as AOA acid)and/or 1H,1H,2H,2H-perfluorooctyltriethoxysilane were prepared on 6N01 Al alloy by a facile,in-situ growth method with enhanced hydrophobicity,anti-biofouling and anti-corrosion performance.The preparation is low energy consumptive and environment friendly,relying on self-assembly at ambient temperature.The structure,molecular weight and functional groups of the synthesized AOA acid were characterized by NMR spectrometer,ESI-MS spectrometer and Fourier transform infrared(FT-IR)spectroscopy.And the compositions,structure and morphology of the films were characterized by Fourier transform infrared(FT-IR)spectroscopy,glancing-angle X-ray diffraction(GA-XRD),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM)and energy-dispersive x-ray spectrum(EDS).Water contact angle measurements(CA)and atomic force microscopy(AFM)characterization show that the films possess a micro/nanostructure with an improved hydrophobicity.Immersion test,neutral salt tests(NSS)and electrochemical impedance spectroscopy(EIS)conducted in 3.5 wt.%NaCl solutions demonstrate the improved corrosion resistance of the films over bare Al alloy.Meanwhile,the films also possess an excellent anti-bacterial property toEscherichia coli,Bacillus subtilis and sulfate-reducing bacteria. 展开更多
关键词 Li-Al layered double hydroxides Anti-biofouling HYDROPHOBICITY Anti-bacterial Anti-corrosion
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Surface-engineering enhanced sodium storage performance of Na_3V_2(PO_4)_3 cathode via in-situ self-decorated conducting polymer route
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作者 Jiexin Zhang tianci yuan +4 位作者 Haiying Wan Jiangfeng Qian Xinping Ai Hanxi Yang Yuliang Cao 《Science China Chemistry》 SCIE EI CAS CSCD 2017年第12期1546-1553,共8页
The key to the development of sodium ion battery is materials with a high rate capacity and cycle stability. Conducting coating is an efficient approach to improve electrochemical performance. As a case study, the Na_... The key to the development of sodium ion battery is materials with a high rate capacity and cycle stability. Conducting coating is an efficient approach to improve electrochemical performance. As a case study, the Na_3V_2(PO_4)_3@PEDOT composite was prepared through an in-situ self-decorated conducting polymer route without further calcination. The Na_3V_2(PO_4)_3 electrode with a 7%poly(3,4-ethylenedioxythiophene)(PEDOT) coating can deliver an initial reversible capacity of 100 mA h g^(-1) at 1 cycle, and 82%capacity retention over 200 cycles. The results also show that the Na_3V_2(PO_4)_3 electrode without and with a thick PEDOT coating exhibits poor electrochemical performance, indicating that an appropriate coating layer is important for improving electronic conductivity and regulating Na-ion insertion. Therefore, this work offers possibility to promote the electrochemical performance of poor-conducting materials in sodium-ion batteries using an in-situ self-decorated conducting polymer. 展开更多
关键词 PEDOT Na3V2(PO4)3 surface coating CATHODE sodium ion batteries
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