Sustainable Production of Biomass-Derived Graphite and Graphene Conductive Inks from Biochar

Graphite is a commonly used raw material across many industries and the demand for high-quality graphite has been increasing in recent years, especially as a primary component for lithium-ion batteries. However, graphite production is currently limited by production shortages, uneven geographical distribution, and significant environmental impacts incurred from conventional processing. Here, an efficient method of synthesizing biomass-derived graphite from biochar is presented as a sustainable alternative to natural and synthetic graphite. The resulting bio-graphite equals or exceeds quantitative quality metrics of spheroidized natural graphite, achieving a Raman I_D/I_G ratio of 0.051 and crystallite size parallel to the graphene layers (L_a) of 2.08 µm. This bio-graphite is directly applied as a raw input to liquid-phase exfoliation of graphene for the scalable production of conductive inks. The spin-coated films from the bio-graphene ink exhibit the highest conductivity among all biomass-derived graphene or carbon materials, reaching 3.58 ± 0.16 × 10⁴ S m^-1. Life cycle assessment demonstrates that this bio-graphite requires less fossil fuel and produces reduced greenhouse gas emissions compared to incumbent methods for natural, synthesized, and other bio-derived graphitic materials. This work thus offers a sustainable, locally adaptable solution for producing state-of-the-art graphite that is suitable for bio-graphene and other high-value products.