Electrochemical Energy Storage: The Indian Scenario
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Technology, have been actively engaged in developing both aqueous and nonaqueous batteries. It is expected that there will be a further surge in various activities in this field within India in view of the national solar mission envisaging distributed energy generation to the tune of several hundreds of GW of renewable energy by the year 2022. It is obvious that the storage capacity has to be developed accordingly in order to harness and optimally use this new paradigm of energy generation and distribution. Although, in the global context, pumped storage, which is a mature and relatively cheap technology, takes the lion’s share with compressed air, along with batteries and capacitors occupying a very small fraction as far as grid-connected storage is concerned, the India-specific requirements may necessitate unique solutions, especially keeping in mind its many remote grid-deprived communities. Among the electrochemical systems, Na−S, flow batteries, and Li-ions are projected to be at the forefront. Indian researchers and industries have acknowledged this renewed requirement on the storage front, and the current status addresses the challenges ahead. Among the various batteries, lead-acid batteries have been the workhorse in India, particularly for railways, telecom, UPS, SLI (automotives), and household applications. Indian companies have acquired state-of-the-art manufacturing facilities for all three types of lead-acid batteries, namely, floodedvented, valve-regulated maintenance-free, and gelled batteries. Commercial batteries possess specific energies of about 30 Wh/ kg with discharge efficiencies between 85 and 95%. As cycle life and specific energies have been major obstacles, there have been attempts to improve mechanical properties and corrosion resistance of lead grids by additive management. The perennial problem of sulfation has been addressed by adding various carbons to the negative plates. Another improvement is the use of lightweight materials such as lead-coated plastic grids and lead foam in place of conventional lead grids. The lightweight batteries show about 15% higher specific energy than those with conventional lead grids. NED Energy, Tata Green, and other start-ups also contribute to the market to some extent. There have also been unorganized small units of lead-acid battery companies working on borrowed technology. The major advantage of lead-acid battery technology is its nearly 100% recyclability of lead. The infrastructure, resources, expertise, and support base from allied industries may come in handy for launching new related systems such as lead− carbon hybrid systems and the soluble lead redox flow battery (RFB), which are at laboratory prototype stages at the moment. Demonstration of lithium-ion batteries for applications in areas of solar/grid connectivity, telecom, and automobile
espite the rise of the Li-ion battery, lead acid batteries still remain the primary means of large-scale energy storage in the world. Reflecting this global scenario, the current industrial output in India is primarily centered around lead-acid battery chemistry; however, there are significant efforts to explore other feasible systems, with considerable progress made, as discussed below (see Figure 1).
Figure 1. Energy storage efforts in India.
Efforts to develop storage batteries in India started as early as in the 1940s with the production and commercialization of flooded lead-acid accumulators by Chloride Industries (India); rechristened as “Exide Industries”, it continues to be the major producer of lead-acid batteries in the country to date. Subsequently, Mysore Electrochemicals and Standard Batteries started production of vented lead-acid batteries. A major commercial breakthrough in lead-acid battery technology was brought about by Amararaja Batteries by introducing maintenance-free valve-regulated lead-acid batteries in 1985. Concomitantly, efforts were initiated to manufacture nickel− cadmium alkaline storage batteries by Tamilnadu Alkaline Batteries, Hyderabad Batteries, and High-Energy Batteries. The present battery market in India is about U.S. $4 billion and is expected to grow by about 5−20%, thanks to unprecedented buoyancy in the power backup segment, booming solar and telecom sectors, and growth in industrial automation. This is in accordance with the views projected by the International Renewable Energy Agency (IRENA): it forecasts a worldwide battery storage capacity increase to about 14000 MW by 2023 in utility scale applications.1 On the academic front, organized battery-related research was initiated in the 1970s with joint efforts of Professor S. Sathyanarayana at the Indian Institute of Science (IISc) and a team of researchers from the Vikram Sarabhai Space Centre (VSSC) to develop space-quality nickel−cadmium cells for the Indian Space Research Organization (ISRO). These batteries were used in Indian satellites in the 1970s. Since then, battery R&D work has leaped forward, and several Indian Institutions, namely the Indian Institute of Science, Central Electrochemical Research Institute (CECRI), and various Indian Institutes of © XXXX American Chemical Society
Received: November 1, 2016 Accepted: November 4, 2016
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available with other existing conventional systems. RFBs utilize circulation of electrolytes stored in external reservoirs/tanks into battery cell stacks that consist of a series of bipolar electrodes and separators. Though in their infancy, there have been recent efforts to develop Pb-based RFBs with outputs of 50−500 W with the help of the National Thermal Power Corporation (NTPC), India. The absence of the need to use any membrane in this particular technology is an advantage, but there are challenges, such as shunt currents, dendrite growth, and oxygen evolution, which need to be mitigated. Zinc− bromine RFBs are a compelling storage option due to their attractive energy density, high cell voltage, high degree of reversibility, and use of low-cost and abundant materials. Despite these advantages and favorable features, commercialization of this battery is impeded due to (i) poor kinetic reversibility, (ii) self-discharge associated with Br2 crossover to zinc compartment, and (iii) short circuit due to zinc dendrites. CECRI’s efforts in this direction are centered on low-cost electrode materials/separators, improvement of cell performance by reducing Br2 crossover, and lightweight electrode fabrication to increase energy density. Development of a 1 kW stack of a Zn−Br2 RFB is underway at CECRI. Though there are several studies on the fundamental aspects of oxygen reduction (ORR) and oxygen evolution (OER) in different media, very few efforts are made in developing metal− air battery systems. Oxygen electrode kinetics and reversibility are major issues, and any development in this direction will propel this technology further in to prototyping and commercialization. Zinc−air batteries with excellent charge− discharge cycles and stable ORR/OER using ceramic nitrides and oxide electrodes have been developed at IISc. Other metal−air systems based on Li and Fe are being studied. One of the earliest battery systems being developed at the laboratory scale is based on nickel−iron chemistry.7 The challenges associated with the commercialization include mitigating hydrogen evolution and corrosion of Fe electrodes. This is being mitigated amicably by the use of additives based on Bi and S to the Fe electrode and is expected to lead to costeffective rechargeable batteries in the near future. India also has an ambitious research program on polymer electrolyte fuel cells under the New Millennium Indian Technology Leadership Initiative (NMITLI), led by National Chemical Laboratories together with National Physical Laboratory and CECRI; within this effort, a variety of fuel cell stacks are being field-tested under a public−private partnership model to take the technology forward for commercialization. In a different context, both IISc and CECRI have established battery engineering and battery performance evaluation centers, where both battery engineering and accreditation facilities for industrial batteries are available with inputs for their quality management. To conclude, India has world-class expertise in materials and electrochemistry, which is vital to battery technology. Therefore, the time is ripe for a concerted national effort to propel this area further with a targeted vision plan and sustained funding that are bound to reap rich dividends to address Indiacentric solutions to the issue of optimal utilization of anticipated renewable as well as well-established conventional sources of energy.
sectors has stimulated enormous interest in both the academic community and industrial sector. Industries that are traditional manufacturers of lead-acid batteries are slowly foraying into lithium-ion batteries, and new companies are emerging with collaborative ventures. The federally funded CECRI of the Council for Scientific and Industrial Research (CSIR) has recently installed a lithium battery fabrication facility at the prototype level. The ISRO has been manufacturing spacequality lithium-ion batteries for its internal use. About a year ago, ISRO assisted in the development of lithium battery packs and demonstrated their use in automotives, particularly for an electric bus for use in the parliamentary complex at New Delhi. On the academic front, there has been consistent progress in the last several years. CECRI has been working on various lithium-rich cathode materials such as Li2Ni0.5Mn0.5SnO4/C for high-rate applications. Together with Tarascon’s group at the College de France, CECRI has contributed to the development of cathode materials based on layered lithiated transition-metal oxides, lithium−manganese spinel oxide, and lithium−iron phosphate. The origin of voltage decay in high-capacity layered oxide electrodes that provides a guide to design new formulations in this new class of high-capacity electrodes based on dual cationic and anionic redox mechanisms was recently explored.2 Efforts at IISc include electrolyte development along with cathodes and anodes based on a variety of nanostructured materials. There are some efforts at various Indian Institutes of Technology to investigate newer classes of materials such as layered molybdenum sulfide, phosphides for high rate capability.3 Other systems based on lithium−sulfur batteries and use of natural organic electrode materials with a high energy density have also been the subject of academic interest in India as they are elsewhere.4 The area of supercapacitors or ultracapacitors has received serious attention among the academic community in India, with various research groups developing electrode and electrolyte materials that have resulted in appreciable publications and patents. Institutions, namely IISc, National Chemical Laboratory (NCL), Indian Institutes of Science Education and Research (IISER), Centre for Materials for Electronics Technology (C-MET), Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), and CECRI among others, are involved in the development of electrode materials that are cost-effective and contain earth-abundant materials.5 Exfoliated or flexible graphite that possess a large surface area is proposed for psudocapacitors both in aqueous and in nonaqueous media. Composites of exfoliated graphite with transition-metal oxides have been shown to yield several hundreds of farads with favorable electrochemical characteristics. Of particular interest is the development of hybrid lead-based supercapacitors, which are essentially an offshoot of lead-acid battery chemistry. Herein, PbO2 along with flexible carbon is used in an acidic electrolyte. The hybrid capacitor−battery combination has shown compelling cycle life and performance.6 This technology is currently being taken further for commercialization. The development of carbon-based electrode materials from natural sources such as plant extracts and leaves is being continually explored by several groups around the country, and such efforts have resulted in cost-effective and high-capacitance electrodes. RFBs are striking electrical energy storage systems for the utilization of renewable energy like solar and wind due to their high energy efficiency, deep discharge ability, low self-discharge, and long cycle life. A unique advantage of RFBs is the decoupling of energy capacity and power density, which is not
S. Sampath D. D. Sarma* A. K. Shukla
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ACS Energy Letters Indian Institute of Science, Bengaluru 560012, India
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AUTHOR INFORMATION
ORCID
D. D. Sarma: 0000-0001-6433-1069 Notes
Views expressed in this Energy Focus are those of the authors and not necessarily the views of the ACS. The authors declare no competing financial interest.
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REFERENCES
(1) International Renewable Energy Agency. http://www.irena.org/ documentdownloads/publications/irena_battery_storage_report_ 2015.pdf (2015). (2) Sathiya, M.; Abakumov, A. M.; Foix, D.; Rousse, G.; Ramesha, K.; Saubanère, M.; Doublet, M. L.; Vezin, H.; Laisa, C. P.; Prakash, A. S.; et al. Origin of Voltage Decay in High-Capacity Layered Oxide Electrodes. Nat. Mater. 2014, 14, 230−238. (3) Sen, U. K.; Mitra, S. High-Rate and High-Energy-Density Lithium-Ion Battery Anode Containing 2D MoS2 Nanowall and Cellulose Binder. ACS Appl. Mater. Interfaces 2013, 5, 1240−1247. (4) Goriparti, S.; Harish, M. N. K.; Sampath, S. Ellagic Acid − A Novel Organic Electrode Material for High Capacity Lithium Ion Batteries. Chem. Commun. 2013, 49, 7234−7236. (5) Sarkar, D.; Shukla, A.; Sarma, D. D. Substrate Integrated NickelIron Ultrabattery with Extraordinarily Enhanced Performances. ACS Energy Lett. 2016, 1, 82−88. (6) Shukla, A. K.; Banerjee, A.; Ravikumar, M. K.; Gaffoor, S. A. U.S. Patent 90036332B2, May 19, 2015. (7) Rajan, A. S.; Sampath, S.; Shukla, A. K. An in situ Carbon-Grafted Alkaline Iron Electrode for Iron-Based Accumulators. Energy Environ. Sci. 2014, 7, 1110.
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