Rechargeable Oxide Ion Batteries Based on Mixed Conducting Oxide Electrodes

Abstract

Mixed conducting oxides are frequently studied as electrode materials for solid oxide fuel or electrolysis cells. However, in principle their ability to change stoichiometry depending on the oxygen chemical potential also enables charge storage typical for battery electrodes: Formally neutral oxygen can be incorporated by annihilating oxygen vacancies and creating electron holes, similar to the incorporation of lithium in lithium ion battery electrodes. Electrodes with different reducibility should thus allow operation of an oxide ion battery. This is exemplified for perovskite‐type La0.6Sr0.4FeO3−δ (LSF), La0.5Sr0.5Cr0.2Mn0.8O3−δ (LSCrMn), and La0.9Sr0.1CrO3−δ (LSCr) electrodes with blocked oxygen surface exchange. Cells with thin film electrodes are prepared by pulsed laser deposition on yttria stabilized zirconia electrolytes. Charge/discharge cycles and impedance measurements are performed on half cells between 350 and 500 °C and related to the materials defect chemistry. Electrode capacities of up to 350 mA h cm−3 and <0.25 % capacity loss over 19 cycles are measured at potentials between 0.2 and −1.1 V versus O2 at 1 bar. Full cells with LSF cathodes and LSCrMn anodes are successfully operated at 350 to 400 °C with electrode related energy densities up to 70 mW h cm−3, coulomb efficiencies >99 % and good cycling performance. This novel type of rechargeable battery may open further application fields such as elevated temperatures (>200 °C), where common cation‐based cells are not applicable so far.

Transmission line revisited – the impedance of mixed ionic and electronic conductors

“…For example, when oxygen ions are incorporated from the electrolyte into an SOEC anode material, they can either move through the electrode and leave it at the surface as molecular oxygen (with electrons entering the current collector) or stay in the anode and thereby increase the oxygen content of the material. 8,17 Due to charge neutrality, also in the second case electrons have to be transferred to the current collector, and thus an electrical current flows through the external circuit.…”

“…In terms of device functionality, this transition constitutes the transformation of an SOFC electrode into an oxygen-ion battery electrode, which can store charge based on the principle of coulometric titration. 17,54…”

A High Temperature Harvestorer Based on a Photovoltaic Cell and an Oxygen Ion Battery

“…Oxygen ion batteries, a novel type of electrochemical energy storage device, serve as energy storing components in our combined energy harvesting/storage device. For a detailed description of the operating principle of oxygen ion batteries we refer the reader to a recently published article, demonstrating operation of a proof of concept OIB . Here, we only briefly repeat the working principle of the OIBs, before we show the characteristics of the specific OIB cell used in this study.…”

“…However, once the cell gets charged, oxygen vacancies are formed in the anode, and its transport resistance becomes much lower. The total cell resistance is then predominantly caused by the ionic transport resistance of the thick YSZ electrolyte and contributions from transport across the interfaces between the electrodes and electrolyte . At 17 μA cm –2 , the average overpotential loss of the OIB cell is 95 mV, corresponding to an internal cell resistance of 5.6 kΩ cm 2 .…”

Isotope Exchange Raman Spectroscopy (IERS): A Novel Technique to Probe Physicochemical Processes In Situ

“…To the best of our knowledge, this is the first time that oxygen tracer exchange processes can be directly followed in real time by any means. This methodology can be readily expanded to other fields of application, including e.g., the study of isotopically labeled Li in Li‐ion batteries and O in new O‐ion batteries, [ 30 ] heralding a new era of tracer‐based experiments.…”