In Chapter 1, a literature review on cellulose nanocrystals (CNCs) and biobased carbon materials was conducted, which focuses on their structural properties, synthesis methods, and applications. In Chapters 2 and 3, research on utilizing MxG-CNC-COOH as a stabilizer for graphene in aqueous systems and as a binder for lithium-ion battery electrodes was presented. In Chapter 4, how grafting alkyl chains onto CNC surfaces affects the dispersion of these modified CNCs in organic solvents such as ethanol was explored. In Chapter 5, building on the findings from Chapter 4, the full dispersion of alkyl-chain-grafted CNC-COOH in DMSO was achieved, and the performance of this CNC-COOH in DMSO suspension as a substitute for the current PVDF/NMP system as a binder for lithium-ion battery cathodes in an anhydrous, NMP-free system was investigated. In Chapter 6, a method for synthesizing highly crystalline bio-graphite using biochar and iron powder as raw materials was developed. Slow cooling was found to be a critical step for the formation of high crystallinity bio-graphite product. And the bio-graphene produced from bio-graphite has shown the highest conductivity among all biobased carbon films or composites in the literature. Extending the work from Chapter 6, in Chapter 7, the influence of biomass composition on bio-graphite product was studied, and much cheaper Iron (III) nitrate was used as a precursor for the iron catalyst to convert MxG into a high-performance lithium-ion battery anode material. The relationship between the structure of bio-graphite and its anode performance was explored. In Chapter 7, one of the intermediates is a porous biochar prepared from iron (III) nitrate and MxG. In Chapter 8, this porous biochar as a support material for polyamines in direct air capture of carbon dioxide was further investigated, and synthesis methods for optimizing its pore structure were developed. Finally, in Chapter 9, all the above research was summarized, and directions for future studies were outlined.