Table 7.

Cost and specifications of electrode materials.

	Electrodes	Dimensions	Price (US$ /g)	Reference
	Anode and Cathode materials
1	40% Pt on Carbon Paper, density 0.03 mg cm−2	5.00 x 5.00 cm,	33,334.00	[251]
2	20% Pt on Carbon Cloth, density 0.03 mg cm−2	5.00 x 5.00 cm,	20,000.00	[251]
3	Reduced graphene oxide	0.25 g	947.20	[252]
4	Graphene oxide	1.00 g	152.40	[252]
5	Graphene paper, density 1.9 g cm−3	29.21 x 64.77 cm,	100.00	[252]
6	Graphite Felt, density 28.5 mg cm−2	20.00 x 20.00 cm,	1.32	[253]
7	Graphene nanoplatelets	500.00 g	0.58	[252]
8	Graphite Plates, thickness 1.27 cm, density 0.066 lb in−3	15.24 x 15.24 cm,	0.21	[254]
9	Graphite Plates, thickness 1.27 cm, density 0.066 lb in−3	20.32 x 20.32 cm,	0.18	[255]
10	Stainless Steel sheet, thickness 0.091 cm, density 1.52 lb ft−2	30.48 x 60.96 cm,	0.08	[256]
	Cathode materials
11	Pt catalysts		150.00	[174]
12	10% Pt/C catalysts		60.00	[257]
13	10% Pt/C catalysts		46.61	[177]
14	10% Pt/C catalysts		40.80	[258]
15	10% Pt/C catalysts		33.00	[232], [259]
16	10% Pt/C catalysts		27.00	[181]
17	Copper		5.53	[172]
18	V2O5-NR/rGO		4.80	[259]
19	Co/Cu@NC		4.20	[233]
20	Fe-N-C		3.50	[174]
21	NPOM		3.00	[178]
22	CoO/MgO@NC		1.80	[232]
23	N-G @CoNi/BCNT		0.30	[177]
24	CuZn catalysts		0.09	[181]

NC = Nitrogen doped carbon; V₂O₅-NR = Vanadium pentoxide nanorods; Fe-N-C = Iron-base Nitrogen-carbon