The EXIST research transfer project xemX uses data-driven high-throughput experiments to discover advanced catalysts for a sustainable energy transition. The development of sustainable green energy technologies is a core element in achieving climate goals. Large-scale deployment of water electrolysis and fuel cells requires both a reduction in cost and an increase in efficiency. Currently, catalysts are a significant cost factor, as they are mostly made of precious metals, their alloys or ceramics. The high prices and low availability of precious metals hinder the implementation of green technologies. The urgently needed low precious metal or even precious metal-free catalysts can be achieved by mastering a higher chemical complexity (e.g. high entropy materials, HEM). However, the discovery of HEMs requires a lot of research and development and is still too slow and expensive. Furthermore, the discovery of new, chemically complex materials using conventional methods is almost impossible due to the immense search space and is currently largely based on a tedious trial-and-error approach. Our recent innovations in high-throughput data-driven experiments enable efficient exploration of polyelemental material systems and offer the possibility of significantly reducing both discovery time and the cost of high-performance catalysts.