Zn@C Core–Shell Nanocomposite for Rechargeable Aqueous Zn//MnO₂ Batteries with Long Lifetime

Abstract

Rechargeable zinc‐based aqueous batteries are a promising candidate for next‐generation energy storage devices because of the high theoretical energy density of Zn as well as the availability, safety, and cheap price of Zn‐based aqueous batteries. A Zn@C core–shell composite is designed to overcome two problems of Zn anodes, that is, the formation of Zn dendrites and the corrosion/loss of Zn anode during the charge–discharge process, influencing the lifetime of Zn‐based aqueous batteries. The prepared Zn@C composite from ZnO@C with electrochemical reduction is robust as the anode for a Zn@C//MnO2 battery, and a 98.8% retention after 400 cycles is obtained at a discharge rate of 5 C. The specific capacitance of Zn@C//MnO2 battery can reach 135 mAh gZn−1 at 3 C, and the energy density of this battery can reach 75.9 Wh Kg−1. The coated carbon layer on Zn/ZnO plays a role in protecting Zn/ZnO from leaching or corrosion by KOH, so the structure of Zn@C is a key factor in improving the cycling lifetime of Zn‐based aqueous batteries.

Towards Understanding the Corrosion Behavior of Zinc‐Metal Anode in Aqueous Systems: From Fundamentals to Strategies

“…In recent years, rechargeable aqueous zinc-ion batteries used neutral or mild acidic electrolytes (e. g., Zn-MnO 2 batteries) and alkaline electrolytes (e. g., Zn-air batteries) have achieved decent developments. [23][24][25][26][27] However, zinc anode still faces grand challenges, which seriously hinder the large-scale application. Besides the issues such as dendrites and deformation, zinc corrosion is a crucial issue, which is the main cause of the decrease in the Coulombic efficiency of RAZMBs.…”

Conversion‐Type Nonmetal Elemental Tellurium Anode with High Utilization for Mild/Alkaline Zinc Batteries

“…It should be noted that, it is generally difficult to obtain good cycle performance in normal alkaline ZIBs with Zn metal as anode. [37] However, when replacing Zn foil with Te, our Te/Ni(OH) 2 full cell attains a long-cycle alkaline ZIB with high capacity and excellent rate performance.…”

Self‐Activated Formation of Hierarchical Co3O4 Nanoflakes with High Valence‐State Conversion Capability for Ultrahigh‐Capacity Zn–Co Batteries

“…While for the Zn electrode (Figure S21, Supporting Information), its surface is completely passivated, and the ion and electron transport rates are affected, leading to the performance decay. [46][47][48] To emphasize the advantages of this electrode, the capacity and energy density of Zn-Co batteries were compared to others reported in the literature, as shown in Figure 4e. Both the capacity (481.4 mAh g −1 ) and the energy density (818.3 Wh kg −1 ) shine among the others, such as Co 3 O 4 nanosheet (162 mAh g −1 and 241 Wh kg −1 ), [18] Co 3 O 4 nanowire (173.6 mAh g −1 and 241 Wh kg −1 ), [19] heterogeneous Co 3 O 4 (230 mAh g −1 and 308.8 Wh kg −1 ), [20] defect-rich Co 3 O 4 (204.8 mAh g −1 and 295.5 Wh kg −1 ), [23] and even the Co 3 S 4 (317 mAh g −1 and 507 Wh kg −1 ).…”