Biomass-Derived Carbon Modified with Conductive Co ₃ (HHTP) ₂ Nanorods as an Efficient Binder-Free Cathode for High-Performance Li–CO ₂ Batteries

Lithium–CO2 (Li–CO2) batteries have become an attractive research focus because of their exceptional theoretical energy density and their capability to convert and utilize carbon dioxide. Nevertheless, their practical development is impeded by the poor electrical conductivity of the resulting Li2CO3 discharge products, significant charge–discharge polarization, and sluggish CO2 reduction/evolution kinetics. This study presents the uniform anchoring of one-dimensional electrically conductive metal–organic framework (Co3(HHTP)2) nanorods onto a carbon wood (CW) membrane, derived from Balsa wood, via a hydrothermal process, resulting in the formation of a Co3(HHTP)2@CW composite cathode. The free-standing composite cathode offers a plethora of catalytically active sites and enables the rapid transport of electrons and ions during electrochemical reactions by leveraging the synergistic combination of the highly one-dimensional conductive Co3(HHTP)2 nanorods and the hierarchical porous structure of biomass-derived CW. The cell assembled with the Co3(HHTP)2@CW composite delivers an areal discharge capacity of 7.26 mA h cm–2 at 50 μA cm–2 and maintains a small voltage gap of 1.29 V. Furthermore, this configuration demonstrates durable cycling for over 1000 cycles under a restricted capacity of 100 μA h cm–2 at 100 μA cm–2. In situ XRD, in situ electrochemical impedance spectroscopy (EIS), and distribution of relaxation time (DRT) analyses demonstrated improved charge-transfer kinetics and the reversible formation and decomposition of Li2CO3 on Co3(HHTP)2@CW. This research offers a sustainable approach to the development of low-cost, meta-organic framework-based biomass carbon composites that serve as efficient and binder-free cathodes for advanced energy conversion and storage systems.