SnO₂ nanocubes/bentonite modified SPEEK nanocomposite composite membrane for high performance and durable direct methanol fuel cells

Tin oxide nanocubes/sulfonated bentonite (SnO₂/sBH) nanocomposite blended with acidified poly ether ether ketone (SPEEK) solid state electrolyte is developed for DMFCs. Morphological investigations reveal the existence of SnO₂ nanocubes on sheet-like structure of sBH and the uniform dispersion of above composite on SPEEK matrix. The layered sheet-like structure of BH act as heat diffusion barrier and the ceramic feature of SnO₂ further improves the thermal stability of a SPEEK membrane. The exposed large surface area of BH and tightly bound water molecules in SnO₂ and -SO₃H sites increase the water retention properties, which consequently enhance the ionic conductivity of SPEEK/sBH/SnO₂ composite membrane. Furthermore, the high aspect ratio of sBH and methanol resistive characteristic of SnO₂ lower the methanol diffusion channels in the sBH/SnO₂ composite membrane. With the coalition of above significant electrochemical properties, SPEEK/sBH/SnO₂ solid electrolyte demonstrates the high DMFC power density and excellent durability, which showers light on the viability of prepared membrane in high performance and durable DMFCs.