For as long as engineers have built batteries, safety and performance have pulled against each other like opposing tides. A team of researchers has now demonstrated, through careful molecular architecture, that a nonflammable phosphate-based electrolyte can sustain thousands of charge cycles in potassium-ion batteries without the rapid decay that once made such designs impractical. The work, supported by China's National Natural Science Foundation, does not deliver a finished product so much as a transferable principle — a reminder that the deepest constraints in technology are often not physi