• Cellulose elementary fibrils (CEFs) are proposed as a deagglomerated binder for high-mass-loading Li battery electrodes, addressing ion/electron conduction pathway continuity.
• CEFs, derived from natural wood, exhibit increased surface area and anionic charge density, promoting uniform dispersion with carbon additives and mitigating interfacial side reactions.
• The CEF-based overlithiated layered oxide (OLO) cathode achieves a high areal mass loading of 50 mg cm–2 and a high specific energy density of 445.4 Wh kg–1, outperforming previously reported OLO cathodes.
• This work demonstrates the potential of sustainable, deagglomerated binders to enable high-performance electrodes that are challenging with conventional synthetic polymer binders.