The Iron-Age of Storage Batteries: Techno-Economic Promises and Challenges

Abstract

In this article, we explore the techno-economic promises and challenges related to iron electrode systems, specifically in the iron-air system. We study the discharge-charge products of an iron-air system in an aqueous electrolyte using an iron-water Pourbaix diagram. Using the discharge-charge products from the Pourbaix analysis, we construct a proposed baseline iron-air cell to estimate the basic voltage and capacity of the cell. This cell is then assembled into a battery pack to analyze the unit cost of a 150-hour iron-air system using a process-based cost model developed from the BatPaC model. With the appropriate choice of materials for an iron-air system, we estimate the total battery pack system cost for iron-air to be about US$25/kWh where the cell material costs are around US$5/kWh. The pack hardware costs, air delivery system, and manufacturing costs together account for over US$20/kWh. Through further engineering improvements, better catalysts, and cell chemistry improvements, the battery pack costs may be reduced further, which is promising for long-duration storage applications.

Reversible Chlorite/Chlorine Dioxide Anion Redox Couple for Low-Cost Energy Storage

“…These chemical costs are much lower than those of well-established rechargeable batteries such as Li-ion chemistries at $20-30/kWh, vanadium redox flow batteries at ~$100/kWh, and zinc-bromine flow batteries at $20-30/kWh, and while higher than iron-air batteries at $1.3/kWh, have the advantage of higher energy efficiency due to the facile electrochemical reaction. 4,5 Rechargeable Zn-ClO2 cells are demonstrated in this work as an example of the use of this redox anion. While the electrochemical oxidation of chlorite to chlorine dioxide is well-known and is the basis for significant commercial production of ClO2, an industrial chemical most widely used for disinfection, 9 the reverse reaction, electrochemical reduction to ClO2 -, appears little studied.…”

“…For example, delivering electricity at cost parity with today's natural gas power plants, about $2,000/kW, requires storage technology with installed cost of $20/kWh if multi-day storage (100h) is required, while a cost of $200/kWh is acceptable if the required storage duration is only 10h. Choosing amongst electrochemical storage technologies, the first of these cost requirements may be met, for example, by low-cost iron-air batteries, 4,5 and the second by Li-ion batteries. 1 Considering scalability, it has been estimated that decarbonization of the global electricity system by midcentury will require as much as 100 TWh of new energy storage to be deployed.…”

Reversible Chlorite Anion/Chlorine Dioxide Redox Couple for Low-Cost Energy Storage

“…Cost-effective and scalable electrical energy storage is critically needed for decarbonization of the electricity system, the electrification of transportation, and decarbonization of industrial production. − To first order, the cost of power generation ($/kW) and the duration (h) over which electric power is delivered determine the required installed cost of storage ($/kWh). For example, delivering electricity at cost parity with today’s natural gas power plants, about $2000/kW, requires storage technology with an installed cost of $20/kWh if multiday storage (100 h) is required, while a cost of $200/kWh is acceptable if the required storage duration is only 10 h. Choosing among electrochemical storage technologies, the first of these cost requirements may be met, for example, by low-cost iron–air batteries , and the second by Li-ion batteries…”

In Situ Hydrogen Evolution Monitoring During the Electrochemical Formation and Cycling of Pressed‐Plate Carbonyl Iron Electrodes in Alkaline Electrolyte

“…Among the various types of metal‐air batteries, iron‐air batteries stand out, given the vast abundance of iron, a decent theoretical energy density of 9677 Wh/L Fe (or 1228 Wh/kg Fe , excl. oxygen uptake), a potentially low price [6] and a preeminent environmental friendliness [7–10] . Moreover, iron is less prone to form dendrites upon electrochemical cycling in alkaline media than zinc, [8,11] with all of the aforementioned aspects ever‐sparking research and commercial interest since the times of Thomas Alva Edison [12,13] .…”