Investigation of Ion and Electron Conduction in the Mixed Ionic-Electronic Conductor- La-Sr-Co-Fe-Oxide (LSCF) Using Alternating Current (AC) and Direct Current (DC) Techniques

Among many mixed ionic electronic conductors (MIECs), lanthanum strontium cobalt iron oxide (LSCF) has been proven as a promising material for use as cathode in SOFCs. The ion and electron conduction in LSCF need to be studied separately. To measure the ionic conductivity of LSCF, YSZ disks were applied to block the electronic current, and multilayered samples were made with YSZ disks in series with an LSCF disk. Both AC and DC techniques were used for the measurements. An LSCF(porous)/LSCF(dense)/LSCF(porous) bar-shaped sample was made to measure the electronic conductivity of LSCF. DC technique was utilized for the measurement. Results show that the ionic conductivity of LSCF is much lower than its electronic conductivity. The ionic conductivity of LSCF increases with increasing temperature (600-900°C), and the electronic conductivity decreases with increasing temperature (600-900°C). Measurements were also made on a foil of silver to investigate oxygen transport through it. From this, oxygen ion conductivity through silver was estimated.

High performance ambipolar organic mixed ionic-electronic conductor for adaptive logic circuits and neuromorphic electronics

Organic mixed ionic-electronic conductors (OMIECs) are central to bioelectronic applications such as biosensors, health monitoring devices and neural interfaces, and have facilitated efficient next-generation brain-inspired computing and biohybrid systems. Most OMIECs are hole-conducting (p-type) materials, while complimentary logic circuits and various biosensors require electron-conducting (n-type) materials too. Here we show an ambipolar mixed ionic-electronic polymer that achieves high on/off ratios with high ambient p- and n- type stability. We highlight the versatility of the material by demonstrating its use as a neuromorphic memory element, an adaptable ambipolar complementary logic inverter, and a neurotransmitter sensor. The ambipolar operation of this material allows for straightforward monolithic fabrication and integration, and opens a route towards more sophisticated complex logic and adaptive circuits.

Porous Mixed Ionic Electronic Conductor Interlayers for Solid-State Batteries

Rechargeable solid-state batteries (SSBs) have emerged as the next-generation energy storage device based on lowered fire hazard and the potential of realizing advanced battery chemistries, such as alkali metal anodes. However, ceramic solid electrolytes (SEs) generally have limited capability in relieving mechanical stress and are not chemically stable against body-centered cubic alkali metals or their alloys with minor solute elements (β-phase). Swelling-then-retreating of β-phase often causes instabilities such as SE fracture and corrosion as well as the loss of electronic/ionic contact, which leads to high charge-transfer resistance, short-circuiting, etc. These challenges have called for the cooperation from other classes of materials and novel nanocomposite architectures in relieving stress and preserving essential contacts while minimizing detrimental disruptions. In this review, we summarize recent progress in addressing these issues by incorporating other classes of materials such as mixed ion-electron conductor (MIEC) porous interlayers and ion-electron insulator (IEI) binders, in addition to SE and metals (e.g., β-phase and current collectors) that are the traditional SSB components. In particular, we focus on providing theoretical interpretations on how open nanoporous MIEC interlayers manipulate β-phase deposition and stripping behavior and thereby suppress such instabilities, referring to the fundamental thermodynamics and kinetics governing the nucleation and growth of the β-phase. The review concludes by describing avenues for the future design of porous MIEC interlayers for SSBs.

Li+-Zn2+ tailored nanostructured metallohydrogel based mixed ionic-electronic conductor

A conductive metallohydrogel (MHG) has been obtained via insitu LiOH deprotonation of Mandelic acid derived ligand H2IML followed by coordination of Zn2+ with an objective to fabricate a mixed ionic-electronic...

Theory of the Electrostatic Surface Potential and Intrinsic Dipole Moments at the Mixed Ionic Electronic Conductor (MIEC)-gas Interface

The local activation overpotential describes the electrostatic potential shift away from equilibrium at an electrode/electrolyte interface. This electrostatic potential is not entirely satisfactory for describing the reaction kinetics of a...