Alkaline electrolysers (AWEs) can be an economical choice to achieve large-scale hydrogen production due to their high development maturity and low material cost. Although pressurised electrolysers coupled with renewable energy sources are essential to power gas applications, AWEs have shown a limited load flexibility under high pressure operating conditions due to the weak gas resistance of the composite separator. Thus, we herein report a highly conductive composite separator which is remarkably superior to the commercial separator, Zirfon PERL 500 separator. Our prepared separator will be expected to allow pressurised AWEs to operate more safely and dynamically over a wider load range