1. Nanocellulose in battery development
Antti Hakala,
Nanotechnology in Forest Biomaterials
Photo of Jeff Fitlow/Rice University.

2. Pricinples of Battery (Lithium-ion)
Cathode (+Poly(vinylidene fluoride))
Separator
Electrolyte
The cathode is typically a metal oxide with a layered structure, for example Lithium Cobalt Oxide or Lithium Manganese Oxide and the anode is typically a graphite. These also usually contain a binder material, typically a fluorinated polymer such as PVdF.
Binder = PVdF has good electrochemical stability, adhesion to electrode and current collector materials but poor mechanical properties which are essential to produce flexible electrodes. Moreover, PVdF requires the use of volatile organic compounds that are often toxic.
These materials are coated with metal foils (aluminium for the cathode and copper for the anode)
Electrolyte is usually liquid, made of a Li salt dissolved into an organic solvent.
Positive and negative electrodes are electrically isolated by a microporous PP/PE separator film to prevent short circuits. It must be chemically and electrochemically stable with regard to the electrolyte and electrode materials and mechanically strong enough to withstand the high tension during battery construction. Disadvantage example is that made of fossil fuels.
Anode (+Poly(vinylidene fluoride))
BASF,
Note!! There are still few disadvatages to overcome!

3. Nanocellulose as binder and separator (1/2)
Graphite + MFC in aqueous solution
High flexibility and low density
Pood cycling performance but low conductivity
Left-hand side: One possible alternative to PVdF is MFC. MFC in solid phase was mixed with graphite in aqueous slurry and poured into a Teflon mould. Film was obtained after evaporation of water. Low conductivity is due to the highly porous MFC, but still it had very good cycling performance. Advantages wanted: Flexibility, biodegreability and renewability and non toxic, quite smooth surface.
Right-hand side: Due to the fact that even though carbon has low price, and good cyclic stability, carbon anodes suffer of poor rate performance due to the slow lithium diffusivity and inflexbile. This was tried to overcome by producing carbon aerogels of bacterial nanocellulose. Carbon aerogels showed superior electrochemical performance due to the high surface area, open 3D network and the crosslinking between carbon nanofibres.
Wang et al. (2014)
Jabbour et al. (2010)

4. Nanocellulose as binder and separator (2/2)
Water should be removed to keep NFC structures as open as possible
A Flexible, mechanically strong battery cell with good cycling properties
Cells could be produced by using existing paper-making procedures!
- A whole battery is produced almost in a same way than paper!
Leijonmarck et al. (2013)

5. Conclusions and future propects
There is potential to have a flexible, but still mechanically strong, and renewable batteries
Batteries can be produced with low-cost by traditional methods
All in all, nanocellulose has many promising properties, such as high surface area, flexibility, possibility to modification (electrochemical properties)
Nano lett. (2014)

6. Opinion regarding to the topic
Johan Olsson,

7. References
Jabbour, L., Roberta, B., Chaussy, D., Gerbaldi, C., Beneventi, D., Cellulose-based Li-ion batteries: a review. Cellulose, 20(4), pp – 1545.
Jabbour, L., Gerbaldi, C., Chaussy, D., Zeno, E., Bodoardo, S., Beneventi, D., Microfibrillated cellulose–graphite nanocomposites for highly flexible paper-like Li-ion battery electrodes. Journals of material chemistry, 20(35), pp – 7347.
Wang, L., Schütz, C., Salazar-Alvarez, G., Titirici, M., Carbon aerogels from bacterial nanocellulose as anodes for lithium ion batteries. RSC Advances, 4(34), pp –
Leijonmarck, S., Cornell, A., Lindbergh, G., Wågberg, L., Single-paper flexible Li-ion battery cells through a paper-making process based on nano- fibrillated cellulose. Journal of Materials Chemistry B: Materials for biology and medicine, 1(15), pp – 4677.