# Upcycling Sugar Cane Biomass into 2G Sugars and Lignin-Derived Biochars for Preparing Carbon-Based Electrodes

## TL;DR

This paper shows how to convert sugar cane waste into useful materials for making carbon-based electrodes.

## Contribution

An integrated method to produce 2G sugars and lignin-derived biochars from sugar cane byproducts for electrode applications.

## Key findings

- Bagasse-derived electrodes showed ORR onset potentials of 0.82 V (soda) and 0.76 V (kraft).
- Straw-derived biochars had higher silicate content and sulfur levels, affecting electrochemical stability.
- Straw-derived electrodes are unstable in alkaline media but have higher conductivity for insertion-type batteries.

## Abstract

Converting lignin
into specialty and bulk chemicals enhances both
the economic viability and the sustainability of biorefineries. Here,
we present an integrated approach to produce monosaccharides, lignin,
and lignin-derived biochars from two underutilized agricultural byproducts:
sugar cane bagasse and sugar cane straw. Modified kraft and soda pulping
yielded digestible pulps, which were readily hydrolyzed into monosaccharides
with glucan conversions ranging from 76% to 96%. The corresponding
pretreatment liquors provided lignins, which were pyrolyzed to obtain
biochars. These biochars were blended with a binder to prepare biochar
inks, which were deposited onto electrodes to create functional electrodes.
SEM-EDX characterization revealed a higher silicate content in straw-derived
biochars and increased sulfur levels in kraft-derived biochars. Such
compositional differences influenced electrochemical stability and
catalytic activity toward oxygen evolution (OER) and oxygen reduction
(ORR) reactions. Bagasse-derived electrodes exhibited modest ORR currents,
with onset potentials of 0.82 V (soda) and 0.76 V (kraft). In contrast,
straw-derived electrodes displayed pronounced electrochemical instability
in alkaline media, limiting their use as catalytic carbons for metal–air
batteries. Nonetheless, their higher conductivity suggests potential
as conductive additives in insertion-type battery electrodes. Overall,
this work illustrates integrated strategies for valorizing agricultural
byproducts, expanding the range of applications for lignin-derived
materials within biorefinery processes.