In a breakthrough study, researchers at the Fritz Haber Institute have uncovered the significance of electron spillover in enhancing the energy storage capacity of metal electrodes used in electrolyzers for hydrogen production. By considering quantum mechanical effects in computer simulations, the team demonstrated that even minimal electron spillover into the aqueous electrolyte can increase storage capacity by more than tenfold. This finding addresses a long-standing challenge where previous simulations underestimated the intrinsic storage capacity of electrode materials due to the neglect of quantum effects. The team's complex simulations revealed that electrons from platinum electrodes penetrate the water layers in the electrolyte, leading to a substantial capacity boost. This discovery paves the way for improving future simulations of electrode materials through a better understanding of electron spillover. Dr. Nicolas Hörmann and Lang Li suggest that integrating electron spillover into classical simulations, possibly through machine learning techniques trained on quantum data, can advance the development of efficient electrolyzer materials. This research not only sheds light on a fundamental aspect of electrolyzer efficiency but also highlights the potential of computational methods in accelerating material discovery for sustainable energy applications.