A new approach to prepare N‐/S‐doped free‐standing graphene oxides for vanadium redox flow battery

Abstract

Summary Nitrogen and sulfur heteroatom‐doped graphene oxide (GO) electrodes were produced with a fast, eco‐friendly, and, more significantly, functional group‐controlled technique, chronoamperometry. N‐doped GOs (N‐GOs) and S‐doped GOs (S‐GOs) as binder‐free positive electrodes were designed to boost the performance of vanadium redox flow battery as the positive electrodes. The prepared as positive electrode materials for vanadium redox battery were characterized with cyclic voltammetry, Raman spectroscopy, X‐ray photoelectron spectroscopy, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy. The electrochemical performance of the prepared GO electrodes was investigated through cyclic voltammetry and electrochemical impedance spectroscopy. While S‐GOs containing S, and O‐containing functional groups were shown high electrical conductivity and stability, N‐GOs, containing N and O‐containing functional groups were slightly lower electrochemical performance. Among the high‐performance electrodes, the S‐GO21 synthesized by applying +2.1 V constant potential via the chronoamperometry method exhibited the best performance as the positive electrode for vanadium redox battery. This electrochemical activity result can be correlated to the more S‐ and O‐containing functional groups on the surface of GO.

Lithium‐Free Redox Flow Batteries: Challenges and Future Prospective for Safe and Efficient Energy Storage

“…Large energystorage devices, when viewed as a full system, lessen the possibility of blackouts caused by net frequency exceedances due to overproduction. [33,34] To achieve this, massive energystorage systems with a minimum 20-year lifespan must be built to provide reliable and affordable energy storage. These largescale devices operate differently from small-scale proof-ofconcept flow batteries.…”

“…These profiles can be flattened (also known as “peak shaving”) using flow batteries. Large energy‐storage devices, when viewed as a full system, lessen the possibility of blackouts caused by net frequency exceedances due to overproduction [33,34] . To achieve this, massive energy‐storage systems with a minimum 20‐year lifespan must be built to provide reliable and affordable energy storage.…”

Review—Flow Batteries from 1879 to 2022 and Beyond

“…We would like to mention here in passing, that the electrocatalytic effects in VRFB reactions is comparatively (to H 2 and O 2 electrocatalysis) weak, often poorly reproducible and time-dependent. [286][287][288][289][290][291][292][293][294][295][296][297][298][299][300][301][302][303][304] We shall note also, that some of the aforementioned "quantum jumps" refer principally to academic innovations, as they have proven hard to scale-up and have not been universally-adopted by the flow-battery industry. 238 In conclusion of this section we shall ask ourselves the question: why do we want to increase the area-specific power of RFB stack ?…”

Electrochemical Energy Storage and Conversion Applications of Graphene Oxide: A Review

“…P-GO/carbon felt electrodes have shown superior performance in the VRFB system with having an energy efficiency up to 80.2% with 180 cycles . RGO, which has shown its potential for various energy storage devices, has been explored in VRFBs. − Heteroatom-doped GO/RGO have been extensively studied as electrodes for redox flow battery applications. − Nia et al have studied phosphorus and sulfur co-doped RGO as a catalyst, by knowing the fact that introducing heteroatoms shows different electronegativities followed by a change in the electronic distribution and possesses a synergistic effect, resulting in higher electrocatalytic activity . This PS-RGO shows remarkable performance, with an energy efficiency (EE) value of 71.61% at 160 mA cm –2 and discharge capacity of 772 mAh with a decent cyclic stability .…”