POSTECH Professor Changshin Jo’s research team confirms the superiority of seawater batteries using chelating agents
Water covers about 70% of the earth’s surface. Furthermore, 97% of all water on Earth is seawater, which is unusable due to its salt content. But what if we could harness its potential as a new source of renewable energy?
Recently, a research team led by Prof. Jo Changshin and Ph.D., Department of Chemical Engineering, Institute of Iron and Energy Materials Technology (GIFT), a POSTECH candidate, Hyebin Jeong (Chemical Engineering), developed a seawater battery incorporating a chelating agent. We have made progress in this area by confirming the excellent performance of (SWB).*1 Their findings were published in the Chemical Engineering Journal.
Lithium-ion batteries are widely used in portable electronics and automotive batteries. However, it is not without its limitations, as depletion of the lithium supply could result in an explosion hazard and render it unusable. To address these challenges, next-generation battery development is currently underway. Among them, a seawater battery that generates electricity using Na ions contained in seawater is a promising option. These batteries offer distinct advantages of easy access to resources and are environmentally friendly as they do not require a separate treatment process.
The high salinity of seawater can be attributed to the presence of Na ions. Na ions are utilized by seawater batteries to generate and store electrical energy as they shuttle between the cathode and anode. However, one of the challenges in using nickel hexacyanoferrate (NiHCF) as an intercalation cathode material for SWBs is that it is prone to defects during manufacturing. To address this issue, the research team used a chelating agent (Sample A) to synthesize He NiHCF and compared its performance with untreated He NiHCF (Sample B) to compare the performance of the chelating agent. Evaluated effectiveness.
Looking at the two samples under a microscope reveals striking differences in shape and structure. Sample B consists of randomly agglomerated nano-sized primary particles to form micro-level particles, while sample A consists of individual 200–300 nm sized cube-shaped particles. Although the individual particle size of sample B is small, multiple particles aggregate into larger aggregate structures, which is not very advantageous for battery fabrication.
The researchers further evaluated the electrochemical performance of both samples. First, when we measured the water content, we found that sample A had less water content than sample B. In general, high water content tends to degrade electrochemical performance. In addition, current and voltage measurements show that sample A has high energy efficiency and capacity.
The research team achieved an epoch-making feat of performing 2,000 charge-discharge cycles using two samples, with sample A showing an astonishing capacity retention rate of about 92.8%. Furthermore, the defect incidence rate, a previous drawback of NiHCF, was observed to decrease to 6% for sample A.
The results of this study demonstrate the superior performance achieved by adding a chelating agent to nickel hexacyanoferrate and using it as a cathode material in seawater batteries. This discovery could facilitate the development of seawater batteries as promising candidates for next-generation energy storage systems.
Original: Is the ocean the solution to usher in an era of green energy?
Than: Pohang University of Science and Technology
