Enhancement on Cycle Performance of Zn Anodes by Activated Carbon Modification for Neutral Rechargeable Zinc Ion Batteries

Abstract

A novel composite anode is prepared by mixing zinc particles with activated carbon (AC) to improve the cycle performance of the neutral rechargeable zinc ion batteries. Galvanostatic charge/discharge cycling tests indicate that the capacity retention of the cell with adding 12 wt% activated carbon in Zn anode is 85.6% after 80 cycles, which is much higher than that of 56.7% for the cell using unmodified Zn anode. X-ray diffraction analysis indicates that the addition of activated carbon can suppress the formation of inactive basic zinc sulfates (Zn 4 SO 4 (OH) 6 · nH 2 0). Morphology, elemental mapping and N 2 adsorption and desorption measurements indicate that the pores of activated carbon can accommodate the deposition of Zn dendrites and insoluble anodic products. As a result, the cycle stability of the Zn anode has been greatly enhanced by activated carbon modification. Compared with other widely used metal anodes, such as lead, cadmium and rare metal mesh, zinc is a non-toxic, abundant, and low cost resource. Since the middle of 19th century, zinc has been used as an excellent anodic material for Zn/Mn, Zn/Ni and Zn/Ag batteries. 1With features such as low cost, environmental benignity and good specific energy, the Zn/MnO 2 system has traditionally provided one of the most popular primary cells for a great number of applications. These attractive characteristics, combined with the growing need of high-performance batteries, have prompted considerable efforts to change its primary nature into a secondary one.In the early 1980s, a rechargeable alkaline Zn/MnO 2 (RAM) has been developed. [1][2][3][4] Over the past three decades, the improvement of this technology has progressed rapidly. However, even now the rechargeability of batteries based on Zn anode in alkaline media remains a significant challenge. It is well known that the capacity of rechargeable alkaline Zn/MnO 2 batteries using both KOH and LiOH electrolytes will dramatically drop to below 50% or even worse at only 40 cycles, meanwhile the columbic efficiency decreases to below 50%. 2,4 It has been pointed out by Y. Shen and K. Kordesch 4 that the capacity fading and columbic efficiency loss of rechargeable alkaline Zn/MnO 2 batteries are mainly attributed to the formation of dendrites and passivation products in Zn anodes. These inactive dendrites or passivation products block the transfer of ions and slow the ion diffusion process, leading to a pronounced anodic capacity fading. [4][5][6][7][8][9][10] In addition, the dendrites can penetrate into the separator and result in an interior short circuit. In the 1990's, the neutral ZnSO 4 solution has been exploited as a replacement for the alkaline electrolyte with some promising results.11-13 Kim et al. 13 reported that addition of 0.1∼0.5 mol L −1 MnSO 4 to 2 mol L −1 ZnSO 4 electrolyte greatly improved the cycle performance of rechargeable Zn/MnO 2 cells. The batteries with aqueous ZnSO 4 electrolyte can be cycled in the potential range of 1.0-1.9 V, where a two-step, two-electron charge-discharge ...

Recent Progress of Rechargeable Batteries Using Mild Aqueous Electrolytes

“…Although these methods are developed in alkaline electrolyte, most of them are also helpful in mild electrolyte. Kang and co‐workers presented a composite anode prepared by mixing metallic zinc particles with AC for zinc battery with mild electrolyte. The activated carbon induce the preferential deposition of anodic products in the pores of activated carbon rather than on the surface of Zn particles (Figure b), which greatly improved the electrochemical reaction kinetics and reversibility of zinc anode.…”

“…b) Schematic illustration of the electrochemical deposition of anodic products in the pores of activated carbon during charge process. Reproduced with permission . Copyright 2015, the Electrochemical Society.…”

Dendrite‐Free Nanocrystalline Zinc Electrodeposition from an Ionic Liquid Containing Nickel Triflate for Rechargeable Zn‐Based Batteries

“…[1] However,the development of rechargeable Zn-based batteries has been hindered mainly by the formation of Zn dendrites during charging,l eading to ac apacity fading or even short circuiting of the cell. [5] Although these strategies are promising,t he battery still suffers reduced anode capacity,low Coulombic efficiency,short cyclelife,and safety issues in aqueous and/or organic electrolytes. [5] Although these strategies are promising,t he battery still suffers reduced anode capacity,low Coulombic efficiency,short cyclelife,and safety issues in aqueous and/or organic electrolytes.…”

“…[2] Many approaches have been proposed to suppress dendritic Zn growth by adding additives to the electrolyte, [3] alloying the Zn anode with other metals, [4] and modifying the Zn anode with organic or inorganic materials. [5] Although these strategies are promising,t he battery still suffers reduced anode capacity,low Coulombic efficiency,short cyclelife,and safety issues in aqueous and/or organic electrolytes. [6] Ionic liquids (ILs) exhibit good electrical conductivity,h igh thermal stability,a nd large electrochemical windows and are promising electrolytes for batteries.…”

Inhibition of Zinc Dendrite Growth in Zinc‐Based Batteries

“…[4-6, 13, 18-23] Therefore, apart from high ionic conductivity,h igh ion selectivity,t ogether with low cost, an ideal separator used in zinc-based batteries musth ave enough mechanical stabilityt oa void being pieced. [4,19,22,43,71,74,78,79] Additionally, their conductivity is comparatively better.A ccordingly,s electing separators with high mechanical and chemical stability,t ogether with great conductivity,i se xtremelyi mportant. So far,c ellulosic materials,p olyolefin, polybenzimidazole (PBI), and so forth have been used as materials to prepare ion exchange membranes, porousm embranes, and nonwoven fabrics as separators for zinc-based batteries.…”