123rd General Meeting of the KCS

Type Symposium
Area Beyond Batteries: Understanding New Types of Energy Storage Technology
Room No. Room 303
Time FRI 09:50-10:10
Code ELEC2-3
Subject Prussian Blue open-framework structure for energy storage and harvesting applications
Authors Hyun-Wook Lee
School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Korea
Abstract Prussian Blue and its analogues (PBAs) have gained great attention due to their interesting properties originating from their flexibility in structure and synthetic methods, allowing a large degree of structural and chemical tunability. PBAs can be prepared by bottom-up assembly of molecular precursors via the formation of continuous chemical bonding between transition metal ions and ligand molecules. These cyanide ligands can enable the long-range charge transport with abundant CN triple bonds that can provide free electrons for electrical conduction. Due to such flexibility in their design and resultant properties, they can have a wide variety of applications including energy storage, harvesting, and catalytic applications. In this talk, I will introduce low-vacancy, sodium manganese hexacyanomanganate (MnHCMn) as a viable cathode material for SIBs. The as-synthesized MnHCMn has nonlinear Mn–N≡C–Mn bonds and containing eight large interstitial sites occupied by Na+ ions. Here, I discovered a novel mechanism wherein small lattice distortions allow for the unprecedented storage of 50% more sodium cations than in the undistorted case. Due to the minimal hysteresis in the galvanostatic charge/discharge curves of the electrochemical cell using Prussian Blue open-framework structures, a different approach is to explore thermodynamic cycles as is common in thermomechanical engines. The thermogalvanic effect, the dependence of an electrode’s electrochemical potential on temperature, can be used for such cycles. In the second part of my talk, the electrochemical thermodynamic cycle for thermal energy harvesting will be introduced. By utilizing novel electrode materials, this system can achieve very high efficiencies at low-temperature ranges.
E-mail hyunwooklee@unist.ac.kr