Effect of Carboxylate Group Positioning on the Electronic Structure and Sodium-Ion Storage Behavior of Bipyridine Dicarboxylate Anodes
- 1Department of Chemistry and Biochemistry
- 2George Mason University
- 3Quantum Science and Engineering Center
Abstract
Understanding how molecular structure influences sodiation thermodynamics and electrochemical properties is important for the rational design of high-performance organic anode materials for sodium-ion batteries. In this work, density functional theory (DFT) calculations were employed to establish the structure–performance relationships governing the sodiation thermodynamics and electrochemical properties of three bipyridine-based dicarboxylate isomers: DPC-6,6′, DPC-5,5′, and DPC-4,4′. Although the three systems possess the same N-doped conjugated backbone, differences in carboxylate positioning significantly influence their electronic structure and sodiation behavior. Frontier molecular orbital analysis reveals that carboxylate positioning modulates the LUMO distribution and HOMO–LUMO gap, thereby influencing charge redistribution during the sodiation process. Stepwise sodiation calculations reveal distinct thermodynamic and redox behaviors among the three isomers. DPC-6,6′ exhibits highly favorable initial Na insertion (ΔG = −46.91 kcal mol-1, 1.02 V), whereas DPC-4,4′ shows enhanced stabilization during subsequent Na insertion due to cooperative structural relaxation. DPC-5,5′ displays comparatively balanced thermodynamic stabilization and moderate redox potentials, indicating a more uniform electrochemical response throughout the sodiation process. Comparative analysis with the experimentally reported 2255-Na system further demonstrates that carboxylate positioning and pyridinic nitrogen orientation strongly influence Na coordination, thermodynamic stabilization, and redox behavior during sodiation. These findings provide molecular-level insights into the structure–property relationships governing conjugated organic anode materials for sodium-ion batteries.
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BibTeX
@misc{bashir2026effect,
title = {{Effect of Carboxylate Group Positioning on the Electronic Structure and Sodium-Ion Storage Behavior of Bipyridine Dicarboxylate Anodes}},
author = {Beenish Bashir and Andre Z. Clayborne},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008204/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008204/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Effect of Carboxylate Group Positioning on the Electronic Structure and Sodium-Ion Storage Behavior of Bipyridine Dicarboxylate Anodes
AU - Beenish Bashir
AU - Andre Z. Clayborne
PY - 2026
DA - 2026/09/02
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008204/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008204/v1
AB - Understanding how molecular structure influences sodiation thermodynamics and electrochemical properties is important for the rational design of high-performance organic anode materials for sodium-ion batteries. In this work, density functional theory (DFT) calculations were employed to establish the structure–performance relationships governing the sodiation thermodynamics and electrochemical properties of three bipyridine-based dicarboxylate isomers: DPC-6,6′, DPC-5,5′, and DPC-4,4′. Although the three systems possess the same N-doped conjugated backbone, differences in carboxylate positioning significantly influence their electronic structure and sodiation behavior. Frontier molecular orbital analysis reveals that carboxylate positioning modulates the LUMO distribution and HOMO–LUMO gap, thereby influencing charge redistribution during the sodiation process. Stepwise sodiation calculations reveal distinct thermodynamic and redox behaviors among the three isomers. DPC-6,6′ exhibits highly favorable initial Na insertion (ΔG = −46.91 kcal mol-1, 1.02 V), whereas DPC-4,4′ shows enhanced stabilization during subsequent Na insertion due to cooperative structural relaxation. DPC-5,5′ displays comparatively balanced thermodynamic stabilization and moderate redox potentials, indicating a more uniform electrochemical response throughout the sodiation process. Comparative analysis with the experimentally reported 2255-Na system further demonstrates that carboxylate positioning and pyridinic nitrogen orientation strongly influence Na coordination, thermodynamic stabilization, and redox behavior during sodiation. These findings provide molecular-level insights into the structure–property relationships governing conjugated organic anode materials for sodium-ion batteries.
ER -