"But very little recycling goes on today. In Australia, for example, only 2–3% of Li-ion batteries are collected and sent offshore for recycling, according to Naomi J. Boxall, an environmental scientist at Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO). The recycling rates in the European Union and the US—less than 5%—aren’t much higher."

Until and unless this recycling rate is provably 50% or higher at the time of an EV sale, you should not diss on a 50% loss of efficiency in electrolysis for an FCEV.