Lignocellulosic and biosourced materials for electrochemical energy conversion and storage

In the last 20 years, the Li-ion battery market has rapidly grown thanks to the extensive diffusion of mobile electronics devices; at the same time, dye-sensitized solar cells emerged as promising low-cost alternatives to silicon devices. In order to lower the cost and reduce the environmental impact of these energy storage and conversion devices, efforts must be devoted to reduce the amount of inactive components in the cell, to substitute synthetic polymer binders/separators and organic solvents with low-cost and biosourced materials and to develop new eco-friendly processes for the manufacture of cell components (both electrodes and electrolyte). Here we review the use of biosourced materials for manufacturing: - Bio-inspired all-paper Li-ion polymer cells, constituted by NMFC-binded paper-electrodes, and NMFC reinforced polymer electrolytes. The use of NMFC as filler/binder leads to produce high performing, safe and extremely flexible electrolytes for LiBs. No organic solvents or synthetic polymer binders are used during the entire electrode/electrolyte/cell preparation process. - Paper-based flexible electrodes and electrolytes for third generation solar cells, useful to lower oil-derived components and typical temperatures used to electrodes processing. This materials platform is promising not only for the sustainable manufacture of energy devices components, but also for their processability at the end of life. For example, the all-paper lithium cell can be easily re-dispersed in water by simple mechanical stirring, as well as common paper handsheets and battery materials can be recovered using well-known water-based recycling process.