采用常规的固相反应法结合机械球磨制备了含碳质量分数23.7%的Li_(2)Ni_(2)(MoO_(4))3@C复合材料,并应用于锂离子电池负极。与纯Li_(2)Ni_(2)(MoO_(4))3相比,Li_(2)Ni_(2)(MoO_(4))3@C具有优异的电化学性能,在电流密度为200 mA ·g^...采用常规的固相反应法结合机械球磨制备了含碳质量分数23.7%的Li_(2)Ni_(2)(MoO_(4))3@C复合材料,并应用于锂离子电池负极。与纯Li_(2)Ni_(2)(MoO_(4))3相比,Li_(2)Ni_(2)(MoO_(4))3@C具有优异的电化学性能,在电流密度为200 mA ·g^(-1)时,50周循环后,可逆容量高达845 mAh·g^(-1)。值得注意的是,Li_(2)Ni_(2)(MoO_(4))3@C的首周库仑效率高达85%。此外,运用循环伏安法对Li_(2)Ni_(2)(MoO_(4))3@C复合物存储锂行为进行了初步探索。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
Lithium(Li)-rich manganese(Mn)-based cathode Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2)(LRNCM)has attracted considerable attention owing to its high specific discharge capacity and low cost.However,unsatisfactory cycle ...Lithium(Li)-rich manganese(Mn)-based cathode Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2)(LRNCM)has attracted considerable attention owing to its high specific discharge capacity and low cost.However,unsatisfactory cycle performance and poor rate property hinder its large-scale application.The fast ionic conductor has been widely used as the cathode coating material because of its superior stability and excellent lithium-ion conductivity rate.In this study,Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2) is modified by using Li_(1.4)Al_(0.4)Ti_(1.6)(PO_(4))_(3)(LATP)ionic conductor.The electrochemical test results show that the discharge capacity of the resulting LRNCM@LATP1 sample is 198 mA·h/g after 100 cycles at 0.2C,with a capacity retention of 81%.Compared with the uncoated pristine LRNCM(188.4 m A·h/g and 76%),LRNCM after the LATP modification shows superior cycle performance.Moreover,the lithium-ion diffusion coefficient D_(Li+)is a crucial factor affecting the rate performance,and the D_(Li+)of the LRNCM material is improved from 4.94×10^(-13) to 5.68×10^(-12)cm^(2)/s after modification.The specific capacity of LRNCM@LATP1 reaches 102.5 mA·h/g at 5C,with an improved rate performance.Thus,the modification layer can considerably enhance the electrochemical performance of LRNCM.展开更多
文摘采用常规的固相反应法结合机械球磨制备了含碳质量分数23.7%的Li_(2)Ni_(2)(MoO_(4))3@C复合材料,并应用于锂离子电池负极。与纯Li_(2)Ni_(2)(MoO_(4))3相比,Li_(2)Ni_(2)(MoO_(4))3@C具有优异的电化学性能,在电流密度为200 mA ·g^(-1)时,50周循环后,可逆容量高达845 mAh·g^(-1)。值得注意的是,Li_(2)Ni_(2)(MoO_(4))3@C的首周库仑效率高达85%。此外,运用循环伏安法对Li_(2)Ni_(2)(MoO_(4))3@C复合物存储锂行为进行了初步探索。
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。
基金Project(51772333) supported by the National Natural Science Foundation of China。
文摘Lithium(Li)-rich manganese(Mn)-based cathode Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2)(LRNCM)has attracted considerable attention owing to its high specific discharge capacity and low cost.However,unsatisfactory cycle performance and poor rate property hinder its large-scale application.The fast ionic conductor has been widely used as the cathode coating material because of its superior stability and excellent lithium-ion conductivity rate.In this study,Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2) is modified by using Li_(1.4)Al_(0.4)Ti_(1.6)(PO_(4))_(3)(LATP)ionic conductor.The electrochemical test results show that the discharge capacity of the resulting LRNCM@LATP1 sample is 198 mA·h/g after 100 cycles at 0.2C,with a capacity retention of 81%.Compared with the uncoated pristine LRNCM(188.4 m A·h/g and 76%),LRNCM after the LATP modification shows superior cycle performance.Moreover,the lithium-ion diffusion coefficient D_(Li+)is a crucial factor affecting the rate performance,and the D_(Li+)of the LRNCM material is improved from 4.94×10^(-13) to 5.68×10^(-12)cm^(2)/s after modification.The specific capacity of LRNCM@LATP1 reaches 102.5 mA·h/g at 5C,with an improved rate performance.Thus,the modification layer can considerably enhance the electrochemical performance of LRNCM.
基金National Natural Science Foundation of China(U20A20337)Natural Science foundation of Qinghai Province(2021-ZJ-903)Major science and technology projects of Qinghai Province(2019-GX-168)。
