Batteries are expected to play a pivotal role in the electrification of a range of sectors, including transport, aerospace and grid-scale storage. Of the next generation battery chemistries, Li-S batteries are a particularly attractive option due to their projected high energy density, low cost, and operating temperature range. However, the chemistry of such systems is complex, involving the electrochemical conversion between two insulating species (S and Li₂S), dissolution and shuttling of soluble intermediates, uncontrolled deposition of cathode and anode species, and large volume expansion; if not carefully regulated, these processes can lead to gradual capacity fade at best, explosive cell failure at worst. Here, we discuss the development of free-standing carbon fibre electrodes that are conductive, lightweight and mechanically robust, and their role in addressing degradation mechanisms arising from volume expansion, polysulfide shuttling, dendrite formation and inventory loss. The fibres were prepared via electrospinning of biomass precursors followed by further heat treatment. The porosity, functionality and conductivity can be tailored by varying the precursor and carefully tuning the treatment conditions, to enable free-standing cathodes with high sulfur loadings, improved redox kinetics and enhanced polysulfide interactions to suppress shuttling and sulfur inventory loss. As anode supports, the carbon fibres provide a lithiophilic substrate for a homogeneous lithium-ion flux and low deposition overpotential, which favours large, uniform and low surface area lithium deposits. Employing UV/vis spectroscopy and optical microscopy to observe operando cell processes, we correlate the surface and structural properties of the carbon fibre electrodes with the ability to suppress polysulfide shuttling and control Li deposition and plating, to allow us to further tune the fibre properties to optimise cycling performance. The assembled cell demonstrates greater capacity retention over long-term cycling than conventional Li-S cathode and anode substrates; additionally, the free-standing configuration allows significant gains in energy density by dispensing with traditional electrode components including the binder, conductive additive and metallic current collector, making this process a promising route to achieving new high-energy-density electrode materials for Li‑S technologies.