核壳结构Ni_(2)P/C/Ni_(2)P的制备、表征及其电化学性能

Preparation, Characterization of Core Shell Structured Ni_(2)P/C/Ni_(2)P and Its Electrochemical Property

以空心的介孔碳球(HMCSs)为载体,在其空腔内部及表面固载Ni(OH)_(2)纳米片,然后通过低温磷化过程,合成具有核壳结构的Ni_(2)P/C/Ni_(2)P复合物.该微观结构一方面具有大的比表面积,当其用作电极材料时,与电解液的接触面积增大,有利于锂离子的嵌入;另一方面其内部具有大的空腔,能够缓解其体积膨胀.此外,空心碳球能改善电极材料的导电性,从而提高其储锂性能.因此,Ni_(2)P/C/Ni_(2)P作为锂离子电池负极材料,在电流密度100 mA/g下,循环200圈后,其容量保持在465 mAh/g. Ni_(2)P/C/Ni_(2)P的制备方法为其他金属磷化物的制备及锂离子电池性能的提高提供了一个新的思路.

Firstly, Ni(OH)_(2)nanosheets were controllably grown both on the surface and in the cavity of hollow mesoporous carbon spheres(HMCSs). Then, Ni_(2)P/C/Ni_(2)P complex with core shell structure was obtained through a low-temperature phosphidation process. The microstructure could increase the contact area between the electrode material and the electrolyte due to large specific surface area, which is helpful for the embedding of lithium ions. Additionally, carbon spheres could improve the conductivity of electrode materials, thus improving the performance of lithium storage. In particular, the inner cavity could supply enough space to compensate the volume expansion. When Ni_(2)P/C/Ni_(2)P was used as the anode material for LIBs, it showed a capacity of 465 mAh/g after 200 cycles at the current density of 100 mA/g. The method could be applied to improve the electrochemical performance of other metal phosphides.