电解二氧化锰表面包覆铋镍和铋镍锰复合物

Surface coating of electrochemical manganese dioxide with Bi-Ni and Bi-Ni-Mn composite

采用液相沉淀法在电解二氧化锰(EMD)表面包覆Bi-Ni及Bi-Ni-Mn复合物,以改善其电化学性能,尤其是循环性能。恒电流充放电测试表明,包覆铋镍复合物能明显改善EMD电极的充放电性能和循环稳定性,综合考虑容量、大电流和循环性能,复合物的最佳组成为Bi0.5-Ni0.5。包覆组成为Mn0.3-Bi0.35-Ni0.35的铋镍锰复合物后,电极的0.2C、1 C和3 C放电性能均明显提高,但循环稳定性无改善。而包覆10%Mn0.3-Bi0.175-Ni0.525复合物后不仅能保持EMD电极的初始容量,也能大幅度提高其循环性能:1 C循环50次后容量保持率达到80%,而空白电极只有49%。

In order to improve the electrochemical properties of electrolytic manganese dioxide （EMD）, especially its cycle stability, Bi-Ni and Bi-Ni-Mn composite were separately coated on its surface by liquid-phase precipitation method. The experimental results show that both the charge-discharge performance and cycling stability of the EMD electrode are improved obviously by Bi-Ni composite coating; considering its discharge capacity, high-current and cycle performance, the best composite is Bi0.5-Ni0.5. On the other hand, the capacity of the electrode at 0.2 C, 1 C and 3 C obviously increases after EMD being coated with the Mn0.3-Bi0.35-Ni0.35 composite, but there is no improvement in its cycle performance. While compared with the pure EMD electrode, the initial capacity of the electrode coated with 10% Mn0.3-Bi0.175-Ni0.525 composite can not only be maintained, but also its cycle performance is obviously improved： after 50 cycles at 1 C, the capacity retention of the latter is 80%, but the former is only 49%.