Anchored Nanoparticles Confined to Porous Scaffolds Improve Cathode Performance and Durability

Electrochemical energy conversion and storage technologies show promise; however, in a majority of the electrochemical systems, the interface between active components is usually of great significance in establishing the functionality of any application of energetic materials.

In a research reported in Nature Communications, a research team headed by Prof. XIE Kui from Fujian Institute of Research on the Structure of Matter (FJIRSM) of Chinese Academy of Sciences described a generic approach of interface engineering to obtain active interfaces at nanoscale by a synergistic control of materials functions and interface architectures.

Solid oxide electrolysis (SOE) is a highly efficient high-temperature method that decreases polarization losses and utilizes process heat to the most. Composite cathodes with interfaces made in situ exhibit considerably improved CO₂ electrolysis and enhanced durability.

Prof. XIE’s team discovered that the redox-manipulated interfaces make the transfer of atomic oxygen easy from the adsorbed CO₂ molecules to the cathode array that determines the electrolysis rate of CO₂ at increased temperatures.

For the cerium oxide system, they determined that the conductivity rebalancing time was considerably decreased from 6400 to 600 s for samples with in situ development of dissolved interfaces, while the oxygen exchange coefficient (K_ex) was improved by ~15 times from 2.0 × 10⁻⁵ to 2.92 × 10⁻⁴ cm seconds⁻¹.

At the same time, they discovered that the conductivity rebalance time considerably declines from 15,490 to 535 seconds for the titanium oxide system with in situ development of dissolved metal nanoparticles, while the oxygen exchange coefficient (K_ex) is increased around seven times, from 2.6 × 10⁻⁵ to 1.78 × 10⁻⁴ cm seconds⁻¹.

The metallic nickel cathodes were analyzed with 80% CO₂/2% CO/Ar at 800 °C under applied voltages of 0.4–1.6 V. The current–voltage (I–V) curves visibly showed the superior performance with 300% improvement for the porous nickel with in situ growth of MnO_x nanoparticles when compared to the bare nickel cathode.

The experimental current density with Cu_0.5Ni_0.5-ceria cathode approaches nearly 1.3 A cm⁻² at 1.6 V, which is a 200% improvement contrary to bare ceria cathode. The current densities with Ni/Nb_1.33(Ti_0.8M_0.2)_0.67O₄ (M = Mn, Cr) cathodes approach approximately 1.6 A cm⁻² with 200% improvement at 1.6 V and 800 °C.

Furthermore, these metal or oxide nanoparticles cultured in situ on porous cathodes generated an active metal-oxide interface that would act as a three-phase limit at the nanoscale. Anchored nanoparticles held within porous scaffolds considerably enhance both cathode performance and durability.