Biowaste Lignin-Based Carbonaceous Materials as Anodes for Na-Ion Batteries

Carbonaceous materials derived from biomass lignin-based precursors are an attractive alternative to the hard carbon materials generally used in Na-ion batteries. In this work, we employed almond shells as biowaste precursors and investigated the impact of the annealing atmosphere (Ar, N2, or Ar/H2) on the physicochemical and the electrochemical properties of the obtained carbonaceous materials. Raman spectroscopy, Brunauer–Emmett–Teller analysis, and scanning electron microscopy indicated a relationship between the porosity and the annealing atmosphere. Under a reductive atmosphere, the surface chemistry of the sample was modified, which had an impact on the electrochemical performance. The materials synthesized under Ar and N2 atmospheres delivered specific charges of ca. 255 mAhg−1, which were sustained for more than 60 cycles, whereas the electrochemical performance of the carbonaceous material synthesized under a reductive atmosphere (Ar/H2) was drastically diminished. Once the optimal synthesis conditions were determined, other lignin-derived biowaste materials, such as walnut shells and scrap wood, were also investigated. Despite having similar physicochemical properties, the carbonaceous material derived from scrap wood exhibited better electrochemical performance (specific charge of 270 mAhg−1), confirming the impact of morphology on the electrochemical performance.