Brewers’ Spent Grains‐Derived Carbon as Anode for Alkali Metal‐Ion Batteries

Herein, the synthesis of a nongraphitizable carbon through cost‐effective pyrolysis of a brewery waste product is reported. It is demonstrated that it is possible to realize hard carbon (HC) with structural and morphological properties from an abundant biomass source with a suitable application in energy storage devices. Resulting HC displays reversible capacities of 334, 112 , and 140 mAh g −1 after 100 cycles at 1C with high charge/discharge efficiency (>99.6%) in Li‐ion, Na‐ion, and K‐ion batteries, respectively. Thus, HC derived from brewers’ spent grains can be considered as promising materials for the realization of advanced metal‐ion batteries.