A Physical Organogel Electrolyte: Characterized by in Situ Thermo-Irreversible Gelation

Supplementary Information

A physical organogel electrolyte: characterized by in situ thermo-irreversible gelation and single-ion-predominent conduction

Young-Soo Kim, Yoon-Gyo Cho, Dorj Odkhuu, Noejung Park* and Hyun-Kon Song*

Figure S1 | Gelation of 2 wt. % PVA-CN in an electrolyte. (a) 1 M LiPF6 in 1:2 (vol.) EC:EMC as the base liquid electrolyte. (b and c) The base electrolyte in presence of 2 wt. % PVA-CN just after addition of the polymer (b) and after being stored at room temperature for 12 h. (d to f) The PVA-CN-containing electrolyte after gelation at 60 oC. The samples were stored in vials in an upright position (b to d) and in a 45o-tilting position (e). The self-standing gel electrolyte monolith templated by a cylinder is shown in (f).

Figure S2 | Elastic behaviour of a cylindrical monolith of the gel electrolyte based on 2 wt. % PVA-CN in 1 M LiPF6 in 1:2 (vol.) EC:EMC as the base liquid electrolyte. (a) Schematic of the experiment. (b to d) The shape of the gel before (b) and during applying pressure (c) and after removing the pressure (d). Also, refer to the supplementary movie.

Figure S3 | PVA and PAN in 1 M LiPF6 in 1:2 (vol.) EC:EMC. PVA is not solube in the electrolyte while PAN is soluble. PAN was not gelated after thermal treatment.

Figure S4 | Binding affinity of EC (as the representative solvent molecule) on PVA-CN, PVA (as the OH-only control) and PAN (as the CN-only control). (a) Binding energy profile with respect to the distance between EC and the polymers: solid circle = PVA-CN; open circle = PVA; horizontal dash-dotted line = the calculated binding energy of PAN at its equilibrium distance. Subscript H indicates hydrogen atom of PVA backbone or cyanoethyl groups. The equilibrium configurations of PVA and PVA-CN are indicated by downward and upward arrows, respectively. (b and c) The equilibrium binding configurations of EC onto PVA (b) and PVA–CN (c). Atoms are depicted as balls: H = white small, C = gray, O = red and N = blue.

Figure S5 | Rate capability of pouch-type lithium-ion-battery full cells using the organogel electrolytes based on PVA-CN (gel.ELF+PVA-CN). Liquid electrolytes (liq.ELF and liq.ELF+Pullulan-CN) are included for comparison. LiCoO2 and graphite were used as cathode and anode, respectively. The cells were charged at 0.2C galvanostatically and then at 4.2 V potentiostatically until their current reached 5 % of 0.2C. Then, they were discharged at the indicated C rates. Q = capacity, % relative to a designed value, 750 mAh.