A High-Performance Rechargeable Iron Electrode for Large-Scale Battery-Based Energy Storage

Abstract

Inexpensive, robust and efficient large-scale electrical energy storage systems are vital to the utilization of electricity generated from solar and wind resources. In this regard, the low cost, robustness, and eco-friendliness of aqueous iron-based rechargeable batteries are particularly attractive and compelling. However, wasteful evolution of hydrogen during charging and the inability to discharge at high rates have limited the deployment of iron-based aqueous batteries. We report here new chemical formulations of the rechargeable iron battery electrode to achieve a ten-fold reduction in the hydrogen evolution rate, an unprecedented charging efficiency of 96%, a high specific capacity of 0.3 Ah/g, and a twenty-fold increase in discharge rate capability. We show that modifying high-purity carbonyl iron by in situ electro-deposition of bismuth leads to substantial inhibition of the kinetics of the hydrogen evolution reaction. The in situ formation of conductive iron sulfides mitigates the passivation by iron hydroxide thereby allowing high discharge rates and high specific capacity to be simultaneously achieved. These major performance improvements are crucial to advancing the prospect of a sustainable large-scale energy storage solution based on aqueous iron-based rechargeable batteries. Large-scale electrical energy storage systems are needed to accommodate the intrinsic variability of energy supply from solar and wind resources.1,2 Such energy storage systems will store the excess energy during periods of electricity production, and release the energy during periods of electricity demand. Viable energy storage systems will have to meet the following requirements: (i) low installed-cost of <$100/kWh, (ii) long operating life of over 5000 cycles, (iii) high round-trip energy efficiency of over 80%, and (iv) ease of scalability to megawatt-hour level systems.2 Rechargeable batteries are particularly suitable for such large-scale storage of electrical energy because of their high round-trip efficiency and scalability. Among the types of rechargeable batteries under consideration are vanadium-redox, sodium-sulfur, zinc-bromine, zinc-air and lithium-ion batteries. 3,4 In addressing the challenges of durability, cost, and large-scale implementation of the foregoing types of batteries, the beneficial features of iron-based alkaline batteries for large-scale energy storage have been largely overlooked. Nickel-Iron batteries have been used in various stationary and mobile applications for over 70 years in the USA and Europe until the 1980s when the iron-based batteries were largely supplanted by sealed lead-acid batteries. Iron-air batteries because of their high specific energy underwent active development for electric vehicles and military applications in the 1970s after the "oil shock" but major research in this area was abruptly discontinued after 1984. Except for some seminal research in India by Shukla et al. during the period 1986-1992, iron electrodes have not received any significant attention. [5][6][7] We e...

Towards the development of safe and commercially viable nickel–iron batteries: improvements to Coulombic efficiency at high iron sulphide electrode formulations

“…In the quest for a highly efficient NiFe battery, different materials and manufacturing strategies have been used; in fact, nickel-iron cells reaching nearly 800 mAh g -1 have been reported [11,12]. These batteries require costly reactants and nano-structuring techniques.…”

A High-Performance Sintered Iron Electrode for Rechargeable Alkaline Batteries to Enable Large-Scale Energy Storage

“…17,44 Such an iron electrode when discharged at 3C-rate showed a utilization of about 0.17 Ah/g, a remarkable improvement over the commercial iron electrode with no more than C/5 rate of discharge capability (Figure 18). The sulfide ions prevented passivation of the iron electrode, allowing such high rates of discharge to be sustained.…”

“…This performance represents a significant improvement compared to the charging efficiency of 55-70% and the recommended discharge Journal of The Electrochemical Society, 164 (2) A418-A429 (2017) A419 rate of 0.2 C of commercial nickel-iron batteries. 17,44 As mentioned earlier, these iron electrodes that were demonstrated in our previous studies were the pressed-plate type. While this fabrication method is relatively inexpensive for manufacturing, fabricating electrodes by sintering of iron powders can offer other significant benefits.…”

“…[37][38][39][40] In the last five years, under an effort funded by ARPA-E at the University of Southern California, Narayanan et al have demonstrated notable improvements in the charging efficiency and discharge-rate capability of iron electrodes. 17,44 Also, there has been a deeper understanding of the formation process and methods to increase charging efficiency. 17,43 The role of sulfides in increasing discharge capacity and the factors affecting the cycle life of iron electrodes have also become better understood.…”

Controlling hydrogen evolution on iron electrodes

“…In the quest for a highly efficient NiFe battery, different materials and manufacturing strategies have been used; in fact, nickel-iron cells reaching nearly 800 mAh/g have been reported [27,39], unfortunately these batteries require costly reactants and nano-structuring techniques. These aspects would certainly influence the final price of the battery thus produced [27,39].…”