Flexible Sustained Ionogels with Ionic Hyperbranched Polymers for Enhanced Ion-Conduction and Energy Storage

Abstract

Flexible and mechanically robust gel-like electrolytes offer enhanced energy storage capabilities, versatility, and safety in batteries and supercapacitors. However, the trade-off between ion conduction and mechanical robustness remains a challenge for these materials. Here, we suggest that the introduction of ionic hyperbranched polymers in structured sustained ionogels will lead to both enhanced ion conduction and mechanical performance because of the hyperbranched polymers' ionically conductive groups and the complementary interfacial interactions with ionic liquids. More specifically, we investigate the effect of hyperbranched polymers with carboxylate terminal groups and imidazolium counterions with various ionic group densities on the properties of ionogels composed of coassembled cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs) as sustainable open pore frame for ionic liquid immersion. The addition of hyperbranched polymers leads to the formation of highly interconnected openly porous, lightweight, and shape-persistent materials by harnessing hydrogen bonding between the polymers and the CNFs/CNCs "frame". Notably, these materials possess a 2-fold improvement in ionic conductivity combined with many-fold increase in Young's modulus, tensile strength, and toughness, making them comparable to common reinforced nanocomposite materials. Furthermore, the corresponding thin-film gel supercapacitors possess enhanced electrochemical cycling stability upon repeated bending with an 85% capacitance retention after 10 000 cycles, promising new insight in the development of simultaneously conductive and flexible gel electrolytes with sustained performance.

Self-Healing Bimodal Sensors Based on Bioderived Polymerizable Deep Eutectic Solvent Ionic Elastomers

“…The bioderived PDES ionic elastomer exhibits a strength of 1.83 MPa and a stretchability of 5.27% like the usual biobased materials with limited mechanical properties (Figure a) . Utilizing a hydrogen bond-driven nanofiller network, the bioderived PDES elastomer with 0.2% PDA@CNC has an outstanding strength of up to 5.39 MPa and an excellent toughness of 4.87 MJ/m 3 because of the greatly improved energy dissipation capability via dense sacrificial bonds (Figure a). , Compared with pure bioderived PDES elastomers, the PDA@CNC-containing elastomers are both robust and tough, demonstrating a maximum increase of 2.95 times in strength and 69.57 times in toughness, which are not available in the elastomers with only CNC (Figures b and S8).…”

Highly stretchable, self-adhesive, ambient-stable, and wide-temperature adaptable hydrophobic ionogels for wearable strain sensors

“…Commonly, good conductivity is very important for the applications of ionogels in soft and flexible devices. 58,59 The conductive properties of the as-prepared ionogels were thus investigated. Fig.…”

Recent developments of nanocomposite ionogels as monolithic electrolyte membranes for lithium‐based batteries

“…These nanocomponents could be of various forms in nanoscale size, including nonmetal oxide, metal oxide, boron nitride (BN), and carbon nanotube (CNT), which will be discussed in the following section. In short, NIGs have been rather attractive for various research areas and potential technological applications in actuators, 33,34 ionic thermoelectric capacitors, 35 solid-state batteries, 36 transistors, 37 wearable sensors, [38][39][40][41][42][43] flexible supercapacitors, [44][45][46][47][48][49][50] and so forth. [51][52][53][54] This is attributed to the unique combination of several significant improved properties that NIGs offer, compared with plain IGs and conventional materials.…”