The rapidly growing lithium battery industry has spurred a high demand for lithium minerals and a subsequent concern about the limited global supply and high cost of these materials. So scientists are searching for alternatives. In terms of energy storage capacity and other electrochemical properties, potassium-ion batteries (PIBs) look more promising than sodium-ion batteries. But PIB development has been hampered by a lack of suitable anode materials, especially ones that can accommodate potassium ions’ larger size than lithium and sodium. Zhixin Chen, Zaiping Guo, and coworkers at the University of Wollongong may have come up with a solution. The team reports that a PIB anode made of an inexpensive composite of Sn4P3 and carbon exhibits high charge capacity, fast charging rates, and voltage characteristics suitable for industrial battery applications (J. Am. Chem. Soc. 2017, DOI: 10.1021/jacs.6b12185). In addition, the electrochemical profile of the material indicates that Sn4P3-carbon anodes have little risk of forming metal dendrites, which have been implicated in battery failure due to short circuiting.