摘要
为提高锌镍电池ZnO的循环充放电性能,采用Bi(NO3)3水解沉积法对ZnO包覆Bi基化合物膜,系统研究了包覆ZnO的微结构和电化学性能。TEM,XRD和EDS表明由Bi6(NO3)4(OH)2O6·2H2O,BiO和Bi2O3组成的Bi基化合物膜包覆在ZnO表面。表面包覆能提高ZnO的循环性能和放电容量,含5.1wt%Bi的包覆ZnO循环性能稳定,平均放电容量为509mAh·g-1,利用率为78%,性能有较大改善。充放电曲线和循环伏安结果均表明包覆Bi基化合物膜能降低锌镍电池的充电平台,加宽放电平台,提高ZnO的电化学活性。包覆Bi基化合物膜能有效减小活性材料与碱性电解液的接触,抑制ZnO的溶解,提高循环稳定性;而包覆膜的微孔结构又可使活性材料接触到电化学反应必须的H2O和OH-,保证了高的放电容量。
A method to improve cycling performance of ZnO by coating ZnO with Bi-based compound film using a hydrolyzing-deposition method was presented in this work. The microstructure and electrochemical properties of the coated ZnO was investigated in detail. TEM, XRD and EDS indicated that a film composed by Bi6（NO3）4（OH）2O6·2H2O, BiO and Bi2O3 was successfully coated on ZnO. Surface modification can improve rate capability and cycle stability of ZnO. The coated ZnO containing 5.1wt% Bi showed the best cycle stability, average discharge capacity of 509 mAh·g^-1 and utilization ratio of 78%. Charging/discharging curves and CV curves showed that the coating with Bi-based compound film decreased the charging plateau voltage, widened discharge plateau and increased electrochemical activity. The surface coating with Bi-based compound film decreased the contact between active material and the electrolyte, suppressed the dissolution of ZnO, and improved cycling stability. The micropore structure in the film made the active materials contact with H2O and OH^- that is necessary for charging/discharge reactions, assuring high discharge capacity of the coated ZnO.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2010年第11期2063-2068,共6页
Chinese Journal of Inorganic Chemistry
基金
浙江省教育厅项目(No.0803076-F)资助
关键词
表面包覆
ZNO
循环性能
锌镍电池
surface coating
ZnO
cycling performance
Zn-Ni battery
