Study On The ZnO Composite Flims As The Anode Of Lithium Ion Battery

Because of poor conductivity and large volume change of ZnO, the capacity of ZnO anode decreases quickly in the cycling process. In this work, the cycling performance and rate performance of ZnO anode were improved effectively by combining ZnO film with other materials.In this paper, we constructed two types of ZnO composite films based on dandelion-liked ZnO film. One type was ZnO-C and ZnO-Cu-C composite film, which were combined ZnO film with C and Cu. The other type was ZnO-MO film, which were combined ZnO film with MnO,CoO,TiO₂,Fe₂O₃. XRD,SEM,EDS,TEM,Raman were used to analyze the chemical composition and micro-nano structure. Electrochemical performances of the composite films were measured by galvanostatic charge-discharge and cyclic voltammetry.The electronic conductivity was improved for the first type of ZnO film by C and Cu coatings. In addition, the volume change of ZnO can be alleviated effectively by combined the ZnO film with C, while the decomposition of Li₂O can be promoted by Cu. When the rate was 234 mA/g, the delithiation capacity of ZnO-C composite film kept at 509 mA·h/g after 50 cycles. The delithiation capacity of ZnO-Cu-C composite film kept at 468 mA·h/g after 50 cycles under the same conditions.The structural stability of the second type of ZnO-MO composite film was excellent. The decomposition of Li₂O was promoted by Mn and Co that formed in the first lithiation process for ZnO-MnO-C and ZnO-CoO-C composite films. When the discharge rate was 234 mA/g, the delithiation capacity of the above two films were 475.5 mA·h/g and 533 mA·h/g, respectively. The function of TiO₂ was keeping the stability of the structure in the ZnO-TiO₂-C composite film. The delithiation capacity of the film was 437 mA·h/g. ZnO-Fe₂O₃ composite film exhibits a different structure and cycling performance and rate performance. At a rate of 400 mA/g, the delithiation capacity of this film kept at 777 mA·h/g after 50 cycles, and capacity retention was 96%. At a rate of 2000 mA/g, the delithiation capacity of ZnO-Fe₂O₃ composite film was 641.2 mA·h/g.