Properties of mesoporous carbon modified carbon felt for anode of all-vanadium redox flow battery

Abstract

A novel anode material for all-vanadium redox flow battery was synthesized by dispersion coating of sol-gel processed (resorcinol-furaldehyde) mesoporous carbon (MPC) onto the surface of polyacrylonitrile carbon felt (CF). The coated samples were then annealed at 900°C and 1100°C and the subsequent morphology, surface chemistry, and electrochemical properties of the MPC coated CF were characterized and compared with an uncoated CF. Addition of the MPC coating is shown to dramatically increase surface area while also increasing the number of active surface oxygen groups particularly for samples annealed at 1100°C. MPC coating shows a mixed effect on electrochemical properties. Characterization with cyclic voltammetry reveals the introduction of MPC coating provides roughly 30% increase in peak current density for the oxidation and reduction reactions of the V(IV)/V(V ) redox couple, which is attributed to the significantly increased number of active reaction sites. However, MPC coating seems to be accompanied by a reduction in conductivity as demonstrated by increased redox peak separation and charge transfer resistance. This negative effect on conductivity can be mitigated by heat treatment (at or above 1100°C) which improves surface graphitization reducing redox peak separation and charge transfer resistance such that it is comparable with uncoated samples.

Na2Ti3O7/C Nanofibers for High‐Rate and Ultralong‐Life Anodes in Sodium‐Ion Batteries

“…The low intensity ratio of D versus G band (I D /I G <1.0) can refer to a certain degree of graphitization in a carbon matrix. The value of I D /I G for Na 2 Ti 3 O 7 /C FNFs is 0.89 via calculation, which represents good electrical conductivity . XPS was further used to explore the elemental composition and valence of Na 2 Ti 3 O 7 /C FNFs.…”

“…The value of I D /I G for Na 2 Ti 3 O 7 /C FNFs is 0.89 via calculation, which represents good electrical conductivity. [30][31][32] XPS was further used to explore the elemental composition and valence of Na 2 Ti 3 O 7 /C FNFs. The various elemental composition is marked in the wide spectrum (Figure 5b) and the high-resolution spectra of C, Na, Ti, O are further displayed in Figure 5c-f, respectively.…”

Electrocatalysis at Electrodes for Vanadium Redox Flow Batteries

“…Decreased peak potential separations in CVs at both electrodes of a VRFB and an energy efficiency of 85.8% were reported, significantly better than 73.4% found with commercial carbon felts. Mesoporous carbon was deposited by a sol-gel process on PAN-based carbon felt and annealed at 1100 • C [228]. The significant increase of peak currents of the positive electrode reaction was attributed to the enlarged surface area cause by the deposited mesoporous material.…”

Rectangular Tunnel‐Structured Na0.4MnO2 as a Promising Cathode Material Withstanding a High Cutoff Voltage for Na‐Ion Batteries

“…With the quick development of society, the problems of energy crisis and environmental pollution are increasingly serious . Therefore, more and more attention has been drawn to new energy . We all know that lithium ion batteries as efficient energy storage devices play an important role in application of new energy .…”