Modification of Nafion® Membrane via a Sol-Gel Route for Vanadium Redox Flow Energy Storage Battery Applications

Table 1

Comparison of basic properties of N-117 and N-117/SiO₂-SO₃H membranes.

Samples	SiO2-SO3H	Thickness	Contact angle	Water uptake	IEC	Permeability
	(wt%)	(µm)	Angle (°)	(wt%)	(mmol/g)	(×10^−6 cm^2/min)
N-117	0.00			21	0.99	3.13
NM-0.5H	1.51			17	1.23	0.20
NM-1H	1.91			17	1.24	0.13
NM-24H	1.99			18	1.24	0.12

The reaction times for NM-0.5H, NM-1H, and NM-24H were 0.5 h, 1 h, and 24 h, respectively.