Silicon and Iron as Resource-Efficient Anode Materials for Ambient-Temperature Metal-Air Batteries: A Review

Abstract

Metal-air batteries provide a most promising battery technology given their outstanding potential energy densities, which are desirable for both stationary and mobile applications in a “beyond lithium-ion” battery market. Silicon- and iron-air batteries underwent less research and development compared to lithium- and zinc-air batteries. Nevertheless, in the recent past, the two also-ran battery systems made considerable progress and attracted rising research interest due to the excellent resource-efficiency of silicon and iron. Silicon and iron are among the top five of the most abundant elements in the Earth’s crust, which ensures almost infinite material supply of the anode materials, even for large scale applications. Furthermore, primary silicon-air batteries are set to provide one of the highest energy densities among all types of batteries, while iron-air batteries are frequently considered as a highly rechargeable system with decent performance characteristics. Considering fundamental aspects for the anode materials, i.e., the metal electrodes, in this review we will first outline the challenges, which explicitly apply to silicon- and iron-air batteries and prevented them from a broad implementation so far. Afterwards, we provide an extensive literature survey regarding state-of-the-art experimental approaches, which are set to resolve the aforementioned challenges and might enable the introduction of silicon- and iron-air batteries into the battery market in the future.

Three-Dimensional Fibrous Iron as Anode Current Collector for Rechargeable Zinc–Air Batteries

“…The magnitude of the peaks is relatively small (<±5 mA/cm 2 ) and would most probably be eliminated when the IF surface has been fully coated by the Zn particles. The peaks were Energies 2020, 13, 1429 6 of 18 in accordance with slight oxidation of iron into Fe 2+ and Fe 3+ ions while reacting with the hydroxide ions from the electrolyte, according to Equations (1)-(3) [30]:…”

Analysis on discharge behavior and performance of As- and B-doped silicon anodes in non-aqueous Si–air batteries under pulsed discharge operation

“…Increased demand on new battery technologies for electrical energy storage devices, possessing very high-theoretical energy densities and being abundant in terms of resource availability motivate the ongoing research on metal-air batteries progressively [1][2][3][4][5][6][7][8][9]. Among the resource-efficient anode materials, the highest theoretical energy densities can be realized with aluminium and silicon; specific energies are 8091 Wh kg Al −1 and 8461 Wh kg Si −1 while energy densities are 21,845 Wh L Al −1 and 19,715 Wh L Si −1 .…”

Effect of 1-octanethiol as an electrolyte additive on the performance of the iron-air battery electrodes

“…Iron-air batteries are promising environmentally friendly battery alternatives, because iron is a widely available, low-cost, safe-to-handle, easily recycled metal [1][2][3]. Iron-air batteries are of particular interest, since they have a high specific energy density 764 W h kg −1 Fe and capacity of 1273 mA h g −1 Fe [4,5].…”

“…The thinness and low density of the positive electrode contribute to the high energy density of iron-air batteries. The electrochemistry of the cell is as follows: During discharge, the iron-electrode undergoes two separate processes, firstly oxidation of metallic iron to form iron hydroxide (1), and then further oxidation to magnetite (2) (or other iron oxides such as goethite, a more detailed explanation of the underlying mechanism can be found in [3,6,7]). The air electrode reduces oxygen obtained from the air surrounding the cell, converting it into hydroxide species (3) within the electrolyte [8,9].…”