The recently rising awareness for a more sustainable cell manufacturing can be expected to gain even more momentum in sight of the announcements from major car manufacturers across Europe and North America to entirely electrify their fleet within the next half-decade^1,2. The implementation of aqueous electrode processing strategies for lithium-ion cathodes is a key step to realize the environmentally benign battery production. To achieve this ambitious goal, most studies focus on the development of non-toxic and abundant active materials and specifically, the implementation of nature-derived, inexpensive binders in combination with the use of water as dispersion agent and solvent provides the great possibility to spare energy-intensive drying procedures and costly dry-room conditions, and thus, will turn the whole battery fabrication more eco-efficient ^3,4.

What could easily be established for graphite anodes – employing water-soluble natural polymers as binder, thus, abolishing the need of toxic and rather costly N-methyl-2-pyrrolidone (NMP) as processing solvent^3,5 – appears more complicated for transition metal oxide-based and imperatively cobalt-free cathode materials, which suffer from lithium leaching and transition metal dissolution when getting in contact with water, which has, so far, rendered the use of aqueous binders very challenging^6,7.

In our group we recently demonstrated the general feasibility for the aqueous processing of several lithium-ion cathode materials, such as high-voltage LiNi_0.5Mn_1.5O₄, by introducing a complementary approach, of suitable processing additives to stabilize the active material surface as well as the electrode/electrolyte/current collector interface⁸. Moreover, we extended our investigations to various binder systems and cathode materials in order to advance the aqueous electrode preparation and move from the well-established lab-scale process towards the fabrication of commercial-scale lithium-ion batteries⁹.

References

1. C. J. Barnhart and S. M. Benson, Energy Environ. Sci., 6, 1083 (2013).
2. D. Larcher and J. M. Tarascon, Nat. Chem., 7, 19–29 (2015).
3. D. Bresser, D. Buchholz, A. Moretti, A. Varzi, and S. Passerini, Energy Environ. Sci. (2018) http://xlink.rsc.org/?DOI=C8EE00640G.
4. A. Kwade et al., Nat. Energy, 3, 290–300 (2018) http://www.nature.com/articles/s41560-018-0130-3.
5. S. F. Lux, F. Schappacher, A. Balducci, S. Passerini, and M. Winter, J. Electrochem. Soc., 157, A320 (2010).
6. M. M. Thackeray, J. Am. Ceram. Soc., 82, 3347–3354 (1999).
7. N. Loeffler et al., ChemSusChem, 9, 1112–1117 (2016).
8. M. Kuenzel et al., ChemSusChem, 11, 562–573 (2018).
9. A. Kazzazi et al., ACS Appl. Mater. Interfaces, 10, 17214–17222 (2018).