Table 2.

Comparison of various membranes and their properties.

Membrane	Preparation Method	Conductivity/Current Density	Temperature	Peak Power Density	Fuel	Ref.
PBI/SNP-PBI nanocomposites	Solution-casting	50 mS cm−1	160 °C	650 mW cm−2	Hydrogen	[60]
SPEEK/PVdF-HFP/SiO2	Solution-casting	8 × 10−2 S cm−1	90 °C	1.5 mW m−2	Microbial	[63]
SPEEK 6% W-TNT	Solution-casting	690 mA cm−2	80 °C	352 mW cm−2	Hydrogen	[66]
PA-doped PBI-sTP2	Spin coating	0.096 S cm−1	150 °C	621 mW cm−2	Hydrogen	[67]
Aquivion/TiO2/ZrO2	Impregnation	0.027 S cm−1	75 °C	1120 mW cm−2	Hydrogen	[69]
The Nafion-ZrNT	Solution-casting	140 mS cm−1	80 °C	982 mW cm−2	Hydrogen	[72]
CTS/BPO4@MWNT	Solution-casting	0.040 S cm−1	80 °C	49.0 mW cm−2	Methanol	[73]
SPEEK/ZSC	Solution-casting	38.10 mS cm−1	80 °C	38.9 mW cm−2	Methanol	[74]
CS/SSiO2@CNTs	Solution casting	35.8 mS cm−1	70 °C	60.7 mW cm−2	Methanol	[75]
NCC/PVA-SHGO-1.0	Solution casting	1.1 × 10−2 S cm−1	80 °C	31.4 mW cm−2	Hydrogen	[78]
PEM doped with 8% PS-MGO	Grafting	0.084 S cm−1	25 °C	78 mW cm−2	Methanol	[80]
polybenzimidazole (PBI)/sulfonated graphene oxide (sGO)	Solution casting	0.118 S cm−1	160 °C	364 mW cm−2	Hydrogen	[82]
PAP100-POSSI5.0	Solution casting	0.105 S cm−1	80 °C	152.37 mW cm−2	Hydrogen	[116]
Pi-POSS15%/Pi-SEBS	Solution casting	69.11 mS cm−1	80 °C	219 mW cm−2	Hydrogen	[92]
sPBT-E62.5/SGO3	In situ polymerization	0.139 S cm−1	80 °C	519.9 mW cm−2	Hydrogen	[93]
C-SPEEK/HPW/GO	In situ polymerization	119.04 mS cm−1	80 °C	876.80 mW cm−2	Hydrogen	[95]
CA-PTFE RCMs	Solution casting	0.210 S cm−1	80 °C	0.85 W cm−2	Hydrogen	[104]
SPEEK/cloisite fibre mats	Solution casting	7.73 mA cm−2	60 °C	1.18 mW cm−2	Methanol	[106]
ss-DNA@GO	Electrostatic layer-by-layer assembly	351.8 mS cm−1	80 °C	255.33 mW cm−2	Methanol	[109]
PU/CNT-CdTe/PU/CS)150/60%PA	Layer-by-layer assembly	6.82 × 10−2 S cm−1	150 °C	-	Methanol	[110]
PU/GO/PDDA/GO)200/60%PA	Layer-by-layer assembly	1.83 × 10−1 S cm−1	150 °C	-	Methanol	[111]
PNs/GO/PNs)es/PA	Layer-by-layer assembly	9.26 × 10−2 S cm−1	150 °C	-	Methanol	[112]