Combination of Zn–NiCo2S4 and Zn–Air Batteries at the Cell Level: A Hybrid Battery Makes the Best of Both Worlds
journal contributionposted on 15.06.2019, 00:00 by Xiaoxuan Wang, Xinxin Xu, Jin Chen, Qiang Wang
High performance batteries are decisive for electric vehicles. Here, to obtain a battery with high voltage and powder density as well as desirable capacity and energy density, a hybrid battery is assembled by integration the merits of Zn–NiCo2S4 and Zn–air batteries in one system at the cell level. In this hybrid battery, the Zn plate acts as an anode, and aqueous alkaline serves as the electrolyte. The cathode is fabricated through self-growth of NiCo2S4 nanotubes on a filter paper derived three-dimensional nitrogen doped carbon carrier, which possesses high specific capacity and excellent four-electron oxygen reduction reaction and oxygen evolution reaction activities. This hybrid battery exhibits two voltage plateaus at 1.75 and 1.08 V, which originates from the Zn–NiCo2S4 and Zn–air batteries, respectively. The specific capacity of this battery reaches as high as 626 mAh·g–1 based on the mass of Zn consumed. Its energy density achieves 688 Wh·kg–1, which outperforms both Zn–NiCo2S4 and Zn–air batteries. Furthermore, the outstanding stability of this hybrid battery is demonstrated by a 400 cycle charge–discharge experiment continued for 400 h. This work creates a precedent for the development of a hybrid battery. More importantly, it also provides a feasible method for the fabrication of high performance power sources by integrating the merits of two totally different devices together.