Molecular catalysts serve as ideal platforms for studying electrocatalytic reaction mechanisms. While current research mainly focuses on modulating central metals or surrounding ligands, the influence of molecular spatial configuration remains largely unexplored. Herein, we synthesized two cobalt complexes with similar ligand environments but distinct spatial geometries, a planar cobalt hexaazamacrocyclic complex (CoHAM) and a non-planar acyclic Co(phen)₂Cl₂, and evaluated their performance in CO₂ reduction reaction (CO₂RR). The planar CoHAM exhibited dramatically superior CO₂RR performance compared to the non-planar Co(phen)₂Cl₂. Through a series of combined analyses using in-situ UV-vis spectroscopy, high-resolution mass spectrometry (HRMS), and Raman spectroscopy, we elucidated the origins of this performance gap by identifying key intermediates and reaction pathways. These findings underscore the critical role of the spatial configuration of molecular catalysts in governing electrocatalytic performance and provide a strategic direction for the rational design of efficient CO₂RR catalysts.

Hybrid ion conductors that transport multiple ionic conductive species provide a useful platform for understanding how mixed-ion transport governs ionic conductivity within a single phase. However, the controlled introduction of multiple mobile ions into solid-state electrolytes and a mechanistic understanding of their migration within the framework remain challenging. Herein, a skeleton-retained Li⁺↔Na⁺ cationic exchange was used to simultaneously induce Li⁺ and Na⁺ cations into the NASICON-type framework of Li_3-xNa_xZr₂Si₂PO₁₂ (0 < x < 3). We show that the interpenetration of NaO₆ and NaO₈ coordination polyhedra significantly influences the ionic conductivity of hybrid ion conductors. Computational analysis indicates that Na⁺ transfer from octahedral NaO₆ sites to octa-coordinated NaO₈ sites is thermodynamically favorable, accompanied by Li⁺ relocation from NaO₈ to tetrahedral LiO₄ environments at former NaO₆ sites, thereby promoting Li⁺/Na⁺ site segregation. The increased occupation of Na⁺ at NaO₈ sites not only suppresses Na⁺ mobility due to bottleneck limitations but also hinders the formation of a continuous Li⁺ migration network, thereby reducing the room-temperature ionic conductivity from 1.78 to 0.50 mS·cm^-1. Upon re-exchange, Na⁺ in the NaO₈ sites is replaced by Li⁺ in penta-coordinated LiO₅, which re-establish percolating ion-transport pathways for Li⁺ and enable reversible recovery of the overall conductivity. These results reveal a fast dual-ion conduction mechanism enabled by the interpenetrating occupation of Li⁺ and Na⁺ across the available sites. This work opens a new avenue for the development of hybrid ion conductors.

Carboxymethyl cellulose (CMC) is a water-processable binder widely used for graphite anodes. However, a microscopic understanding of why the identity of CMC counterions (Li⁺/Na⁺/K⁺) strongly affects electrode performance remains limited. Here, molecular dynamics (MD) simulations are used to track Li⁺ transport accessibility across electrolyte/CMC/graphite three-phase interfaces, comparing pure CMC-Li, CMC-Na, CMC-K, and mixed-counterion CMC binders. We find that CMC-Li sustains a continuous Li⁺ transport pathway from the electrolyte through the binder phase toward graphite. In contrast, in CMC-Na and CMC-K, Na⁺/K⁺ ions preferentially enrich at the graphite/binder interface, forming a cation-enriched interfacial layer which reduces Li⁺ accessibility to graphite. Partial replacement of Na⁺/K⁺ in CMC-Na and CMC-K with Li⁺ weakens this interfacial blocking effect and increases Li⁺ accessibility. Furthermore, a stage-resolved kinetic analysis visualizes the progressive suppression of Li⁺ crossing the binder phase upon the barrier layer formation. These results provide a microscopic rationale for the experimentally observed performance advantage of CMC-Li over CMC-Na and CMC-K binders.