A Green Solution to Energy Storage: Brewers’ Spent Grains Biocarbon–Silica Composites as High‐Performance Lithium‐Ion Batteries Anodes

Abstract

The demand for more efficient energy storage devices has become increasingly important in order to face the ongoing energy transition. In this regard, it is equally important to attain the production of these devices with the lowest possible environmental impact. In light of this, the use of waste materials and low‐polluting methods has become a strategic priority. In this study, brewers’ spent grains were utilized as raw material to produce anodic electrodes for lithium‐ion batteries (LIBs). The synthesis process involves only two pyrolysis steps at low temperatures without any chemical treatment, reducing energy investment and waste generation. The result is a porous biocarbon structure—with mixed graphitic and amorphous characteristics—decorated with silica nanoparticles. The presence of silica greatly enhances storage capacity. The obtained biocarbon based electrodes exhibites a capacity of 455 mAh g−1 after 100 cycles, surpassing the standard anode material commonly used in commercial LIBs.