Front Cover: Mechanochemical Deep Impact: Delivering Sustainable Synthesis and Hydrogen Innovation (ChemSusChem 4/2026)

The Concept by K.-i. Saitow (DOI: 10.1002/cssc.202502650) introduces mechanochemistry in planetary ball mills as a transformative and sustainable chemical platform in which mechanical impact is converted into reaction-driving energy. High-energy collisions between balls, analogous to meteorite impacts on Earth, generate transient extreme pressures and temperatures and supercritical water in microscale “hot spots,” allowing reactions once restricted to high-temperature or solvent-intensive laboratory or industrial conditions to proceed. This platform achieves hydrogen evolution efficiencies comparable to those of electrolysis and even realizes a new phenomenon: room-temperature thermochemical water splitting.