Name: MD ADIL
Department: Energy Science and Engineering
Name of supervisor: Prof. Sagar Mitra
Description of research work: Aqueous Calcium-ion Battery Option for Large-Stationary Storage
Md. Adil1, Ananta Sarkar1, Amlan Roy1, Manas Ranjan Panda,1,2, Abharana N2 and Sagar Mitra1,*
1Electrochemical Energy Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, India
2IITB-Monash Research Academy, Mumbai - 400076, India
3Bhabha Atomic Research Centre, Mumbai - 400085, India
Aim of the research work: To develop low-cost, high-rate capable aqueous full-cell calcium-ion battery
The high-rate cycling capability, volumetric capacity, and environmental benignity at a low-cost define the ingress of the upcoming energy storage devices. The urge of such energy storage devices comes into the picture because today, the state-of-the-art, non-aqueous lithium-ion battery (LIBs) technology is ineffectual to improve its rapid-charging ability beyond a specific limit on a commercial scale. Recently, aqueous multivalent-ion batteries (Ca2+, Mg2+, Zn2+, and Al3+) heed the research attention as a safe supplement to lithium-ion batteries due to their low-cost, high-rate cycling capabilities, easiness of fabrication, high-safety, desired volumetric energy-density with amplified faradic storage capability. Besides, multivalent-ions can provide more electrons in a single redox reaction under the same conditions giving high specific capacity. Among multivalent-ion-based batteries, Ca2+ batteries have attracted keen interest because Ca2+ has a reduction potential (-2.87 V vs. SHE) close to Li (-3.04 V vs. SHE), high volumetric capacity (2073 mA h mL-1) and faster diffusion kinetics due to low charge density, which results in higher reversible capacity.
Here, we demonstrate the feasibility of a fast, safe, and stable calcium-ion battery system for the first time. Less expensive polyaniline based anode and inorganic Prussian blue compound were used to construct the battery, and that can cost a few dollars/kWh of electricity and can be considered as an option for stationary storage instead of hazardous lead-acid batteries.
Experimental Section (methodologies adopted)
Synthesis of Copper hexacyanoferrate cathode (CuHCF)
Copper hexacyanoferrate nanoparticles were synthesized by a wet chemical co-precipitation method. Typically, using an equal volume of a 0.1 M Cu(NO3)2.2.5H2O (SigmaAldrich, ≥ 98%) and 0.05 M K3Fe(CN)6.3H2O (Fisher Scientific, 98%) aqueous solution.
Synthesis of Polyaniline (PANI)-Coated Carbon Cloth anode (PANI/CC)
An in-situ polymerization reaction prepared the electrode sheet of PANI/CC according to the previously reported method. Briefly, several pieces of carbon cloth were treated with an acid solution. The pre-treated carbon cloth was completely soaked in a solution containing a calculated amount of aniline and ammonium persulfate, keeping the solution in an ice bath for 24 hours under vigorous stirring.
Most significant results
The as-fabricated aqueous Ca-ion battery with polyaniline anode, and a calciated copper hexacyanoferrate (CaxCuHCF) cathode, delivers an energy density of 70 Wh kg-1 at 250 W kg-1. It even maintains 53 Wh kg-1energy density at 953 W kg-1with an excellent rate capability and achieves a new record in aqueous calcium-ion batteries. The battery exhibits an initial discharge capacity of 125 mAh g-1, and it maintained 95% of the initial discharge capacity at the end of 200 cycles. This Ca-ion battery exhibited an excellent rate performance with a high Coulombic efficiency value even at a higher current rate. This significant battery performance is suitable for large-scale grid application where high-rate performance and safety is the most important criteria.
Novelty/Application of this research work
This novel rechargeable aqueous Ca-ion battery features low-cost, non-toxic, and easily scalable electrode materials, a better counterpart in comparison to non-aqueous batteries reported in the literature. The use of non-toxic, non-flammable, and inexpensive aqueous electrolyte makes the manufacturing environment-friendly, cost-effective, and effortless. This battery is competitive with vanadium flow, lead-acid, Ni-metal hydride, and other reported full-cell metal-ion batteries. This technology could find applications in large-scale energy storage devices and grid-level energy storage applications, including the smoothing of the intermittent fluctuation in the power generation.
In this work, we have fabricated an aqueous Ca-ion battery comprising of a polyaniline anode and a calciated copper hexacyanoferrate cathode in a 2.5 molar Ca(NO3)2 aqueous electrolyte. Polyaniline is investigated for the first time as an anode in aqueous rechargeable Ca-ion battery. The fabricated Ca-ion battery delivers not only good cycling performance but also excellent rate capability. It provides an average specific capacity of 130 mAh g-1 at a current rate of 0.8 A g-1 with 95% capacity retention over 200 charge-discharge cycles. In a country like India, where energy storage devices with low-cost, long calendar life with high volumetric energy density are in high demand. We believe that this aqueous Ca-ion battery with high safety, low-cost electrode materials, and high volumetric capacity could encourage stationary energy storage applications at a vast scale in India and around the globe in the near future.
Electrochemical performances of rechargeable aqueous full-cell Ca-ion battery
Figure 1. Electrochemical performance of the full-cell: (a) the schematic representation of the full-cell. (b) Cyclic voltammogram of the PANI/CC anode, calciated CuHCF cathode, and the linear sweep voltammetry of carbon cloth current collector at a scan rate of 1 mV s-1 in aqueous 2.5 M Ca(NO3)2 electrolyte at 20 ± 2 oC accuracy. (c) Potential vs. charge-discharge capacity profiles at the current rate of 0.8 A g-1 at 20 ± 2 oC accuracy. (d) Long-term cycling performance at the current rate of 0.8 A g-1. (e) Charge-discharge profiles at different current rates. (f) Rate performances at various current rates.
Figure 2.Comparison of commercial batteries with this aqueous Ca-ion battery: (a) A Ragone plot comparison of aqueous Ca-ion battery with commercial lead-acid and Nickel-metal hydride batteries. (b) A schematic representation showing the superiority of aqueous Ca-ion battery over the lead-acid battery and its various applications.
Reference of this aqueous Ca-ion battery
Adil, Md, Ananta Sarkar, Amlan Roy, Manas Ranjan Panda, Abharana Nagendra, and Sagar Mitra. "Practical Aqueous Calcium-Ion Battery Full-Cells for Future Stationary Storage." ACS Applied Materials & Interfaces 12, no. 10 (2020): 11489-11503.