TY - JOUR
T1 - Synthesis, characterization, and theoretical insights of green chitosan derivatives presenting enhanced Li+ ionic conductivity
AU - Cardoso, J.
AU - Nava, D.
AU - García-Morán, P.
AU - Hernández-Sánchez, F.
AU - Gomez, B.
AU - Vazquez-Arenas, J.
AU - González, I.
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/3/5
Y1 - 2015/3/5
N2 - The synthesis, thermal, dielectric and conductivity properties of functionalized chitosan polymer derivatives are evaluated to determine their potential uses as a nontoxic electrolyte/separator for lithium batteries. Deacetylated chitosan (DAC) at 97% is used as a precursor to prepare two derivatives: N-propylsulfonic acid chitosan (SC), chitosan with zwitterionic pendant groups (ZWC). These derivatives increase the polar character of pure chitosan, and significantly improve its solubility. Likewise, they are thermally stable up to 220 C, and their glass transition temperatures (Tg) are located in the region where they decompose, except for SC (Tg = 158 C). The incorporation of the sulfobetaine and zwitterionic pendant groups improves the ionic conductivity by at least 2 orders of magnitude with respect to pure chitosan at 25 C, without the use of plasticizers or further modifications. The salt addition (LiPF6 or LiClO4) to ZWC does not modify the conductivity, whence it is suggested that its increase is due to an electronic modification, such that the energy barriers for conducting the Li+ across the ZWC become decreased (i.e., charge dislocation), rather than a salt dissociation. This experimental finding is confirmed with density functional theory (DFT) calculations conducted with the SC and ZWC structures.
AB - The synthesis, thermal, dielectric and conductivity properties of functionalized chitosan polymer derivatives are evaluated to determine their potential uses as a nontoxic electrolyte/separator for lithium batteries. Deacetylated chitosan (DAC) at 97% is used as a precursor to prepare two derivatives: N-propylsulfonic acid chitosan (SC), chitosan with zwitterionic pendant groups (ZWC). These derivatives increase the polar character of pure chitosan, and significantly improve its solubility. Likewise, they are thermally stable up to 220 C, and their glass transition temperatures (Tg) are located in the region where they decompose, except for SC (Tg = 158 C). The incorporation of the sulfobetaine and zwitterionic pendant groups improves the ionic conductivity by at least 2 orders of magnitude with respect to pure chitosan at 25 C, without the use of plasticizers or further modifications. The salt addition (LiPF6 or LiClO4) to ZWC does not modify the conductivity, whence it is suggested that its increase is due to an electronic modification, such that the energy barriers for conducting the Li+ across the ZWC become decreased (i.e., charge dislocation), rather than a salt dissociation. This experimental finding is confirmed with density functional theory (DFT) calculations conducted with the SC and ZWC structures.
UR - http://www.scopus.com/inward/record.url?scp=84924163160&partnerID=8YFLogxK
U2 - 10.1021/jp5128699
DO - 10.1021/jp5128699
M3 - Article
AN - SCOPUS:84924163160
SN - 1932-7447
VL - 119
SP - 4655
EP - 4665
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 9
ER -