A Bipolar Redox Metal-Organic Framework for Metal-Conversion-Free Symmetric Halide-Ion Batteries
- 1University of Vienna
- 2Heyrovsky Institute of the CAS
Abstract
Rechargeable batteries predominantly rely on cation intercalation or metal conversion reactions, which often suffer from structural degradation, limited reversibility, and safety concerns. We report a symmetric halide-ion battery based on a bipolar redox metal-organic framework (MOF), in which energy storage is governed by reversible intraframework halogenation rather than metal--halide conversion chemistry. The bipolar redox chemistry of the μ 3 -oxo-bridged trinuclear copper centres in the MOF enables reversible halogenation and dehalogenation, allowing identical electrodes consisting of MOF microcrystals embedded within binder-free carbon nanotube (CNT) films to function as either cathode or anode depending on the halide species involved. Operando Raman spectroelectrochemistry reveals the underlying redox mechanism, while density-functional theory (DFT) suggests a thermodynamic preference for bromination over chlorination, rationalising the framework's dual functionality. In a symmetric configuration using a mixture of chloride- and bromide-based neat ionic liquids, the cell reaches a specific capacity of 68.7 mAh g -1 and an energy density of 35.4 Wh kg -1 under extended charging conditions. The cell operates for more than 200 charge--discharge cycles under repeated short-charge cycling. This non-flammable, moisture-resistant system composed entirely of earth-abundant elements highlights the potential of redox-active MOFs for alternative battery chemistries.
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BibTeX
@misc{kohminaei2026bipolar,
title = {{A Bipolar Redox Metal-Organic Framework for Metal-Conversion-Free Symmetric Halide-Ion Batteries}},
author = {Danial Kohminaei and Shiraz Ahmed Siddiqui and Alexander Prado-Roller and Hidetsugu Shiozawa},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv-2025-9tf68/v2},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv-2025-9tf68/v2},
note = {CC BY},
}
RIS
TY - UNPB
TI - A Bipolar Redox Metal-Organic Framework for Metal-Conversion-Free Symmetric Halide-Ion Batteries
AU - Danial Kohminaei
AU - Shiraz Ahmed Siddiqui
AU - Alexander Prado-Roller
AU - Hidetsugu Shiozawa
PY - 2026
DA - 2026/09/09
PB - ChemRxiv
DO - 10.26434/chemrxiv-2025-9tf68/v2
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv-2025-9tf68/v2
AB - Rechargeable batteries predominantly rely on cation intercalation or metal conversion reactions, which often suffer from structural degradation, limited reversibility, and safety concerns. We report a symmetric halide-ion battery based on a bipolar redox metal-organic framework (MOF), in which energy storage is governed by reversible intraframework halogenation rather than metal--halide conversion chemistry. The bipolar redox chemistry of the μ 3 -oxo-bridged trinuclear copper centres in the MOF enables reversible halogenation and dehalogenation, allowing identical electrodes consisting of MOF microcrystals embedded within binder-free carbon nanotube (CNT) films to function as either cathode or anode depending on the halide species involved. Operando Raman spectroelectrochemistry reveals the underlying redox mechanism, while density-functional theory (DFT) suggests a thermodynamic preference for bromination over chlorination, rationalising the framework's dual functionality. In a symmetric configuration using a mixture of chloride- and bromide-based neat ionic liquids, the cell reaches a specific capacity of 68.7 mAh g -1 and an energy density of 35.4 Wh kg -1 under extended charging conditions. The cell operates for more than 200 charge--discharge cycles under repeated short-charge cycling. This non-flammable, moisture-resistant system composed entirely of earth-abundant elements highlights the potential of redox-active MOFs for alternative battery chemistries.
ER -