DC05 - Luxembourg Institute of Science and Technology - Luxembourg
Title: Synthesis of single-ion conducting diblock copolymers combining soft ionic segments and high-performance aromatic blocks
Objective:
DC5 will develop a library of novel, up-scalable self-assembled single-ion block copolymers (SIBCs). The work will start from the synthesis of anionic monomers having covalently bonded bis-(trifluoromethylsulfonyl)imide anion, epoxide functional group and a lithium cation free to move. Further on, a series of single-ion conducting soft blocks (SI) will be prepared by controlled cationic ring-opening (co)polymerization (CCROP), of ethylene oxide (EO) and an anionic epoxy monomer. For lithium metal polymer (LMP) batteries the SIBCs containing a rigid second block will be synthesized by chain extension of the SI soft block by ROP of trimethylene carbonate. For Li/S batteries the second route towards SIBCs will involve robust, orthogonal and efficient covalent ligation by Click chemistry (i.e. Cu(I)-catalyzed azide-alkyne cycloaddition) of the azide soft block SI and a series of rigid functional aromatic polyethers (e.g. sulfone, thioether, fluorinated) obtained via a general polyaddition strategy and carrying complementary clickable alkyne chain ends. A systematic study of structure-properties correlations (i.e. both block chemical structure and composition especially regarding the Li content and block volume ratios) will be carried out to investigate this novel class of polyether-based SIBCs. Finally, the best performing materials will be upscaled (>0.2 kg) and applied in the assembly of LMP and Li/S batteries.
Expected results:
DC5 will firstly focus on the synthesis of new anionic monomer with epoxide functional group. Then, he/she will obtain a series of SI and SIBCs varying the length and the ratio of blocks by combination of controlled cationic ring-opening (co)polymerization (CCROP) and click chemistry. The resulting SIBCs are expected to yield self-assembled microstructures with long-range order. Soft SI polyether blocks with non-crystalline PEO side-chains are expected to provide unprecedented ionic conductivity and Li ion mobility. The rigid blocks suppose to serve as stiffener imparting mechanical reinforcement, and yielding robust, high performance membranes with high Li+ mobility. Thorough structure-properties correlations will be established, in collaboration with DC7 (POLITO, Torino, Italy) and the best performing materials are supposed to show enhanced properties (e.g. σ > 2 × 10-4 S/cm at RT, tLi+ ~ 1 and ESW ~ 5 V Li/Li+, etc.).
The most promising SIBCs will be implemented into lab-scale LMP (in collaboration with DC7, POLITO) and Li/S (in collaboration with DC6, NIC, Ljubljana, Slovenia) batteries (coin and pouch cells) and later on scaled-up in collaboration with SP (Castries, France) to assemble pre-industrial battery demonstrators.
SUPERVISORS
