An in situ carbon-grafted alkaline iron electrode for iron-based accumulators

In this work, we have studied a 2% copper substituted core shell type iron/iron carbide as a negative electrode for application in energy storage. The NanoFe-Fe 3 C-Cu delivered 367 mAh g −1 at ≈80% current efficiency, successfully running for over 300 cycles. The superior electrode kinetics and performance were assessed by rate capability, galvanostatic, potentiodynamic polarization measurements in 6 M KOH electrolyte and at ambient temperature. Ex-situ XRD characterizations and SEM images of both the fresh and used electrode surfaces show that nanoparticles were found to be still intact with negligible particle agglomeration. The electrodes have shown stable performances with low capacity decay, whereas sulfur dissolution from the additive Bi 2 S 3 was found to decrease the charging efficiency with time. This core-shell type structured nano material is, consequently, an auspicious anode candidate in alkaline-metal/air and Ni-Fe battery systems. Electricity generation away from fossil fuels by renewable energy resources (RER) is increasing at a remarkable pace both as a means of mitigating greenhouse gas emissions as well as offsetting the global energy demand for sustainable development. Since the end of the 1990s, the world cumulative energy generation by both wind and solar has shown an exponential growth rate. In 2015, the global installed capacity of photovoltaics was 227.1 GW an increase by 25% and the total installed wind power was 432.9 GW, a rise by 17% compared to 2014 for both energy systems.1,2 However, both wind and solar are very dependent on weather conditions and there is a high quest for electrical energy storage (EES) for integration with these renewables. The variability in energy output is due to the stochastic nature and availability of the renewable sources, unreliable demand and supply of electricity, distributed energy generation, maintenance and utilization of load balance in peak shaving and leveling, stabilization of transmission and distribution to the grid, uninterruptable power supply with frequency control, voltage fluctuations and energy arbitrage. EES is considered to be vital and indispensable technology for both utility and transport applications.1,3-7 Among EES technologies, electrochemical energy storage systems in the form of batteries have characteristic features in the form of modularity and scalability, fast response time and high energy efficiency, although they do significantly differ in energy and power densities, charge and discharge duration, cycling behavior and capital cost.There are several rechargeable (secondary) battery energy storage systems (BESS) that are widely used or are under demonstrations/development phases and these among others include; lead-acid, Li-ion, the nickel-based batteries (Ni-MH, Ni-Cd, Ni-Fe, Ni-Zn, NaNiCl 2 ), redox flow batteries (Vanadium, Zn-Br, Zn-Cl, Zn-Ce, FeCr, V-Br), NaS and Air-metal batteries (Fe-air, Zn-air, Li-air, Mgair).6-10 The last type of "batteries" are essentially a hybridization of anodes in the form of metals and a f...

Section: Resultsmentioning

confidence: 93%

Core/Shell Structure Nano-Iron/Iron Carbide Electrodes for Rechargeable Alkaline Iron Batteries

Paulraj

Kiros

Skårman

et al. 2017

“…Similarly, a gradual loss in capacity in about 100 cycles following formation has been observed by Shukla et al with in situ carbon-grafted iron electrode prepared with bismuth sulfide additive. 13 In the case of the iron electrode with bismuth sulfide additive, the loss of the in situ formed iron sulfides and the accumulation of magnetite during repeated cycling manifests in a loss of electrode capacity (Figure 17a). The addition of sodium sulfide to the electrolyte of this electrode leads to capacity recovery in the short term (Figure 17a).…”

Section: Fesmentioning

confidence: 99%

“…The promise of iron-based batteries for large-scale energy storage has spurred renewed interest in their development. 11,[13][14][15][16] The development of iron-based alkaline batteries began several decades ago. [17][18][19][20][21][22] In the US, development of iron-air and nickel-iron batteries for electric vehicle applications was primarily undertaken by the Westinghouse Corporation and Eagle Picher Industries.…”

mentioning

confidence: 99%

“…More recently, a carbon-grafted iron electrode with a high specific capacity and high discharge rate capability has been reported. 13 Cycling properties of the iron electrode.-To achieve the targeted LCOE for large-scale energy storage, the batteries must have a long cycle life. 3,5,39 For example, at a battery cost of $100/kWh, to realize an LCOE of $0.025/kWh, about 5000 deep cycles of charge and discharge without significant loss in capacity will be required.…”

mentioning

confidence: 99%

See 1 more Smart Citation

The Role of Sulfide Additives in Achieving Long Cycle Life Rechargeable Iron Electrodes in Alkaline Batteries

Manohar

Yang

Narayanan

2015

Iron-based alkaline rechargeable batteries such as nickel-iron and iron-air batteries are promising candidates for large-scale energy storage applications because of their relatively low cost, inherent robustness to cycling, and eco-friendliness. In the present study, we demonstrate iron electrodes containing iron (II) sulfide and bismuth oxide additives that do not exhibit any noticeable capacity loss even after 1200 cycles at 100% depth of discharge in each cycle. In iron electrodes prepared with bismuth sulfide additive, capacity loss occurred during cycling, accompanied by a decrease in discharge rate capability and rapid passivation. The recovery of capacity by adding sulfide ions to the electrolyte confirmed that the electrode that suffered capacity fade did not have an adequate supply of sulfide ions. We also found that the loss of cycleability was accompanied by the steady accumulation of magnetite and loss of iron sulfides at the iron electrode. The use of sparingly soluble iron (II) sulfide as an electrode additive ensured a sustained and steady supply of sulfide preventing the accumulation of magnetite during cycling. Thus, we have gained understanding of the critical role of sulfide additives in achieving long cycle life in rechargeable alkaline iron electrodes. Inexpensive and efficient methods of storing electrical energy are essential for the successful integration of solar and wind-based electricity generation into the grid. Among the various means to store electrical energy at a large scale, batteries are particularly promising because of their advantages of high energy efficiency, modularity and flexibility to siting.1-4 The state-of-art commercially-available lithium-ion, lead-acid, nickel-metal hydride and vanadium redox flow batteries may be rated by the levelized cost of energy delivered (LCOE). LCOE is calculated as the ratio of the cost (including capital and operating costs) to the total amount of energy delivered by the battery over its useful lifetime. The LCOE for commercially-available batteries is at least five to ten times higher than the DoE targets of $0.10 to $0.20/kWh. 5,6 Also, since energy storage will be required at the scale of thousands of gigawatt-hours, we are faced with the challenge of providing a sustainable solution, as the global material reserves are quite limited for these state-of-art batteries.7 Therefore, the development of inexpensive, efficient, robust and sustainable battery systems for grid-scale energy storage is a topic of intense research.3-6 Under an effort funded by ARPA-E, we have been focusing on developing such batteries. 7,[8][9][10][11][12] Iron-based battery systems such as nickel-iron and iron-air batteries are based on raw materials that are relatively inexpensive, globally-abundant, and eco-friendly. The promise of iron-based batteries for large-scale energy storage has spurred renewed interest in their development. 11,[13][14][15][16] The development of iron-based alkaline batteries began several decades ago. [17][18][19][20][21][22] In the U...

“…7,8 Rechargeable iron-based alkaline batteries such as nickel-iron and iron-air have unique advantages that make them particularly attractive for meeting the emerging demands of grid-scale electrical energy storage systems. 6,[9][10][11][12] Iron, the primary raw material for these battery systems, is globally abundant, relatively inexpensive, eco-friendly and is recycled readily. Thus, iron is particularly attractive as a raw material for batteries required at such a large scale.…”

mentioning

confidence: 99%

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

Yang

Manohar

Narayanan

2017

Iron-based alkaline rechargeable batteries such as iron-air and nickel-iron batteries are particularly attractive for large-scale energy storage because these batteries can be relatively inexpensive, environment-friendly, and also safe. Therefore, our study has focused on achieving the essential electrical performance and cycling properties needed for the widespread use of iron-based alkaline batteries in stationary and distributed energy storage applications. We have demonstrated for the first time, an advanced sintered iron electrode capable of 3500 cycles of repeated charge and discharge at the 1-hour rate and 100% depth of discharge in each cycle, and an average Coulombic efficiency of over 97%. Such a robust and efficient rechargeable iron electrode is also capable of continuous discharge at rates as high as 3C with no noticeable loss in utilization. We have shown that the porosity, pore size and thickness of the sintered electrode can be selected rationally to optimize specific capacity, rate capability and robustness. These advances in the electrical performance and durability of the iron electrode enables iron-based alkaline batteries to be a viable technology solution for meeting the dire need for large-scale electrical energy storage. Electrical energy storage systems will enable the seamless integration of the electricity generated from wind turbines and solar photovoltaics into the electricity grid. Rechargeable batteries are particularly good candidates for such large-scale energy storage because of their high round-trip efficiency, inherent scalability, and flexibility for being located almost anywhere.1-6 Batteries such as vanadiumredox, lead-acid and lithium-ion are under consideration for this application because of their commercial availability. Yet, the widespread deployment of these battery systems is limited by their materials cost, lifetime, safety concerns, and the high cost of delivered energy. 7,8Rechargeable iron-based alkaline batteries such as nickel-iron and iron-air have unique advantages that make them particularly attractive for meeting the emerging demands of grid-scale electrical energy storage systems.6,9-12 Iron, the primary raw material for these battery systems, is globally abundant, relatively inexpensive, eco-friendly and is recycled readily. Thus, iron is particularly attractive as a raw material for batteries required at such a large scale.6 Iron-based batteries such as the nickel-iron battery are historically well known for their extraordinary robustness to thousands of cycles of charge and discharge, and tolerance to overcharge and over-discharge. [13][14][15][16] Such robustness is generally uncommon among rechargeable batteries; other types of batteries in use today degrade in about 1000 cycles.17 For example, lead-acid batteries typically offer 500-800 cycles, and lithium-ion batteries usually last no more than 1000 cycles especially when subjected to deep discharge.18 Despite these striking attributes of iron-based batteries, the large-scale use of these batteries ...