针对AZ31镁合金作为镁电池负极时存在自腐蚀速率大、阳极极化、电位滞后等问题,寻找合适的缓蚀剂及其用量调配电解液以提高电池的放电性能。通过腐蚀浸泡试验表征了缓蚀剂Li_(2)CrO_(4)的缓蚀效果,然后通过极化曲线、电化学阻抗谱研究了...针对AZ31镁合金作为镁电池负极时存在自腐蚀速率大、阳极极化、电位滞后等问题,寻找合适的缓蚀剂及其用量调配电解液以提高电池的放电性能。通过腐蚀浸泡试验表征了缓蚀剂Li_(2)CrO_(4)的缓蚀效果,然后通过极化曲线、电化学阻抗谱研究了Mg(ClO_(4))_(2)溶液中Li_(2)CrO_(4)用量对AZ31镁合金电化学性能的影响,最后通过组装水系镁锰电池进行恒流放电作为应用端测试。结果表明:Li_(2)CrO_(4)能够使AZ31镁合金的腐蚀电位正移,最大正移量达到150 m V,在水系镁锰电池应用中能够提高镁电池的放电平台,当Li_(2)CrO_(4)质量分数为0.7%时放电平台提高0.15 V左右;当Li_(2)CrO_(4)质量分数为1.2%时,其能够显著改善AZ31镁合金在Mg(ClO_(4))_(2)溶液中的腐蚀,水系镁锰电池放电容量达最大,为196.9 m A·h,相对空白溶液,电池的放电容量提高约64%,工作电压高达1.39 V且放电曲线稳定。展开更多
To meet the demand for high-performance LiCoO_(2) batteries,it is necessary to overcome challenges such as interface degradation and rapid capacity degradation caused by changes in bulk structure,especially under deep...To meet the demand for high-performance LiCoO_(2) batteries,it is necessary to overcome challenges such as interface degradation and rapid capacity degradation caused by changes in bulk structure,especially under deep delithiation and high temperature conditions.The ion conductive coating layer of Li_(3)PO_(4) has been directly modified on the surface of LiCoO_(2) particles using magnetron sputtering method,significantly improving the lithium storage performance of LiCoO_(2)@Li_(3)PO_(4) composites.Compared to pure LiCoO_(2),the modified LiCoO_(2) sample exhibits obviously better cycle life and high-temperature performance.Especially,under the conditions of 2 and 1 C,the LiCoO_(2)@Li_(3)PO_(4) electrode delivers excellent cycling performance at high voltage of 4.5 V,with capacity retention rates of 89.7%and 75.7%at room temperature and high temperature of 45℃,being far greater than those of 12.3%and 29.1%for bare LiCoO_(2) electrodes.It is discovered that the Li_(3)PO_(4) coating layer not only effectively enhances interface compatibility and suppresses the irreversible phase transition of LiCoO_(2),but also further improves the Li^(+)transport kinetics and significantly reduces battery polarization,ultimately enabling the modified LiCoO_(2) electrode to exhibit excellent lithium storage performance and thermal safety characteristics under high voltage conditions.Thus,such effective modified strategy can undoubtedly provide an important academic inspiration for LiCoO_(2) implication.展开更多
以五氧化二钒干凝胶、碳酸锰、磷酸二氢铵、碳酸锂、乙炔黑为原料,采用固相法在相对较低的温度条件下合成了x Li Mn PO4·y Li3V2(PO4)3锂离子电池复合正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)对其晶体结构和表面形貌进行表征...以五氧化二钒干凝胶、碳酸锰、磷酸二氢铵、碳酸锂、乙炔黑为原料,采用固相法在相对较低的温度条件下合成了x Li Mn PO4·y Li3V2(PO4)3锂离子电池复合正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)对其晶体结构和表面形貌进行表征。结果表明,750℃下烧结15 h合成的3Li Mn PO4·Li3V2(PO4)3为结晶良好的两相结构,颗粒粒径较小且分布比较均匀,其在室温、0.2 C倍率下首次充放电容量分别为144.8 m Ah/g和139.8 m Ah/g,循环50次后容量为130.5 m Ah/g。展开更多
通过溶胶-凝胶法制备了Li_2FeSiO_4@C/CNTs(LFS@C/CNTs)纳米复合材料,其中三嵌段共聚物P123用作结构导向剂和碳源,碳纳米管作为导电线提高材料的导电性。LFS@C/CNTs不仅具有海绵状纳米孔,能够与电解液充分接触改善锂离子的传输路径,同...通过溶胶-凝胶法制备了Li_2FeSiO_4@C/CNTs(LFS@C/CNTs)纳米复合材料,其中三嵌段共聚物P123用作结构导向剂和碳源,碳纳米管作为导电线提高材料的导电性。LFS@C/CNTs不仅具有海绵状纳米孔,能够与电解液充分接触改善锂离子的传输路径,同时由非晶碳和碳纳米管构成的三维桥联导电网络利于电子的快速传递,提高了材料大电流充放电能力和循环稳定性。复合后的LFS@C/CNTs的高倍率性能相比LFS@C明显提高,当CNTs的掺量为4%,电压窗口为1.5~4.5 V,0.1C电流密度下放电比容量为182 m Ah·g^(-1)。在10C经70次循环后该材料的放电比容量能保持在117 m Ah·g^(-1),是LFS@C放电比容量(55 m Ah·g^(-1))的两倍。展开更多
文摘针对AZ31镁合金作为镁电池负极时存在自腐蚀速率大、阳极极化、电位滞后等问题,寻找合适的缓蚀剂及其用量调配电解液以提高电池的放电性能。通过腐蚀浸泡试验表征了缓蚀剂Li_(2)CrO_(4)的缓蚀效果,然后通过极化曲线、电化学阻抗谱研究了Mg(ClO_(4))_(2)溶液中Li_(2)CrO_(4)用量对AZ31镁合金电化学性能的影响,最后通过组装水系镁锰电池进行恒流放电作为应用端测试。结果表明:Li_(2)CrO_(4)能够使AZ31镁合金的腐蚀电位正移,最大正移量达到150 m V,在水系镁锰电池应用中能够提高镁电池的放电平台,当Li_(2)CrO_(4)质量分数为0.7%时放电平台提高0.15 V左右;当Li_(2)CrO_(4)质量分数为1.2%时,其能够显著改善AZ31镁合金在Mg(ClO_(4))_(2)溶液中的腐蚀,水系镁锰电池放电容量达最大,为196.9 m A·h,相对空白溶液,电池的放电容量提高约64%,工作电压高达1.39 V且放电曲线稳定。
基金jointly supported by the Natural Science Foundations of China(No.22179020,12174057)Fujian Province’s“Young Eagle Program”Youth Top Talents Program。
文摘To meet the demand for high-performance LiCoO_(2) batteries,it is necessary to overcome challenges such as interface degradation and rapid capacity degradation caused by changes in bulk structure,especially under deep delithiation and high temperature conditions.The ion conductive coating layer of Li_(3)PO_(4) has been directly modified on the surface of LiCoO_(2) particles using magnetron sputtering method,significantly improving the lithium storage performance of LiCoO_(2)@Li_(3)PO_(4) composites.Compared to pure LiCoO_(2),the modified LiCoO_(2) sample exhibits obviously better cycle life and high-temperature performance.Especially,under the conditions of 2 and 1 C,the LiCoO_(2)@Li_(3)PO_(4) electrode delivers excellent cycling performance at high voltage of 4.5 V,with capacity retention rates of 89.7%and 75.7%at room temperature and high temperature of 45℃,being far greater than those of 12.3%and 29.1%for bare LiCoO_(2) electrodes.It is discovered that the Li_(3)PO_(4) coating layer not only effectively enhances interface compatibility and suppresses the irreversible phase transition of LiCoO_(2),but also further improves the Li^(+)transport kinetics and significantly reduces battery polarization,ultimately enabling the modified LiCoO_(2) electrode to exhibit excellent lithium storage performance and thermal safety characteristics under high voltage conditions.Thus,such effective modified strategy can undoubtedly provide an important academic inspiration for LiCoO_(2) implication.
文摘以五氧化二钒干凝胶、碳酸锰、磷酸二氢铵、碳酸锂、乙炔黑为原料,采用固相法在相对较低的温度条件下合成了x Li Mn PO4·y Li3V2(PO4)3锂离子电池复合正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)对其晶体结构和表面形貌进行表征。结果表明,750℃下烧结15 h合成的3Li Mn PO4·Li3V2(PO4)3为结晶良好的两相结构,颗粒粒径较小且分布比较均匀,其在室温、0.2 C倍率下首次充放电容量分别为144.8 m Ah/g和139.8 m Ah/g,循环50次后容量为130.5 m Ah/g。
文摘通过溶胶-凝胶法制备了Li_2FeSiO_4@C/CNTs(LFS@C/CNTs)纳米复合材料,其中三嵌段共聚物P123用作结构导向剂和碳源,碳纳米管作为导电线提高材料的导电性。LFS@C/CNTs不仅具有海绵状纳米孔,能够与电解液充分接触改善锂离子的传输路径,同时由非晶碳和碳纳米管构成的三维桥联导电网络利于电子的快速传递,提高了材料大电流充放电能力和循环稳定性。复合后的LFS@C/CNTs的高倍率性能相比LFS@C明显提高,当CNTs的掺量为4%,电压窗口为1.5~4.5 V,0.1C电流密度下放电比容量为182 m Ah·g^(-1)。在10C经70次循环后该材料的放电比容量能保持在117 m Ah·g^(-1),是LFS@C放电比容量(55 m Ah·g^(-1))的两倍。
