Boosting the Performance of Graphene Cathodes in Na–O₂ Batteries by Exploiting the Multifunctional Character of Small Biomolecules

Abstract

Graphene aerogels derived from a biomolecule‐assisted aqueous electrochemical exfoliation route are explored as cathode materials in sodium–oxygen (Na–O2) batteries. To this end, the natural nucleotide adenosine monophosphate (AMP) is used in the multiple roles of exfoliating electrolyte, aqueous dispersant, and functionalizing agent to access high quality, electrocatalytically active graphene nanosheets in colloidal suspension (bioinks). The surface phenomena occurring on the electrochemically derived graphene cathode is thoroughly studied to understand and optimize its electrochemical performance, where a cooperative effect between the nitrogen atoms and phosphates from the AMP molecules is demonstrated. Moreover, the role of the nitrogen atoms in the adenine nucleobase of AMP and short‐chain phosphate is unraveled. Significantly, the use of such cathodes with a proper amount of AMP molecules adsorbed on the graphene nanosheets delivers a discharge capacity as high as 9.6 mAh cm−2 and performs almost 100 cycles with a considerably reduced cell overpotential and a coulombic efficiency of ≈97% at high current density (0.2 mA cm−2). This study opens a path toward the development of environmentally friendly air cathodes by the use of natural nucleotides which offers a great opportunity to explore and manufacture bioinspired cathodes for metal–oxygen batteries.

Transition Metal Nanoparticle-Embedded Nitrogen-Doped Carbon Nanorods as an Efficient Electrocatalyst for Selective Electroreduction of Nitric Oxide to Ammonia

“…Similar turbostratic nature is observed in all other TM-NCNR samples at a lower annealing temperature of 700 °C with an I D / I G ratio close to 1 (Figure S14). In addition, Ni-NCNR samples exhibit a 2D characteristic peak at ≈2700 cm –1 attributed to sp 2 -bonded planar graphene . This 2D band explains the presence of graphene layers in Ni-NCNR samples, which is confirmed by HR-TEM results (Figure g).…”

Unveiling the Role of Tetrabutylammonium and Cesium Bulky Cations in Enhancing Na‐O2 Battery Performance

“…[ 41 ] However, they presented a very limited cyclability in the case of electrolyte without additive, much lower than that reported for similar systems in other works. [ 11,14,62,63 ] In the case of the cesium salt (Figure 5c), the improvement in cyclability is notable. A clear enhancement in cycling stability is observed, reaching over 90 cycles with a coulombic efficiency ≥ 90%.…”

“…Higher current densities lead to more filmlike growth dominated by the surface-mediated mechanism, while low current densities lead to a solution-mediated type mechanism. [8] In addition, materials parameters such as the surface properties of the oxygen electrode, [9][10][11] the nature of solvent, [18,[12][13][14] and salt [15,16] which formed the electrolyte, the salt concentration in the electrolyte [17] or the use of certain additives [18,19] can also modify the dominant mechanism of the ORR. The presence of traces of water in the electrolyte can also alter the mechanism of formation and growth of the discharge products.…”

Alternative anodes for Na–O2 batteries: the case of the Sn4P3 alloy

“…Based on these discoveries, research has focused mainly on the design of new air electrodes with new morphologies or the modication of their surface with different molecules and compounds that facilitate the catalysis of the oxygen reduction and evolution reactions (ORR/OER). [5][6][7] Carbon materials have been mostly studied as Na-O 2 battery cathodes due to their low cost, high surface area, chemical stability, high conductivity, developed porosity and intrinsic catalytic activity towards the ORR/OER. 5,[7][8][9][10] Lately, the electrolyte has received considerable attention from the scientic community.…”

“…[5][6][7] Carbon materials have been mostly studied as Na-O 2 battery cathodes due to their low cost, high surface area, chemical stability, high conductivity, developed porosity and intrinsic catalytic activity towards the ORR/OER. 5,[7][8][9][10] Lately, the electrolyte has received considerable attention from the scientic community. Different formulations have been explored that allow a greater stabilization of the discharge products within the electrolyte in order to avoid the blockage of active sites in the air electrode with insulating products such as sodium superoxide (NaO 2 ) and the occurrence of parasitic reactions.…”