Controlling Dendrite Growth with Xylan-Enhanced Hydroxyl-Rich Hydrogel Electrolyte for Efficient Zn-Ion Energy Storage

Abstract

The development of sustainable and safe energy storage systems is becoming increasingly important, which will drive the boom of aqueous Zn-based energy storage devices. However, it is challenging to overcome the dendrite and side-reaction issues of Zn anodes and extend the applications of devices. Herein, we design a polysaccharide-enhanced hydrogel electrolyte (PBXHE: PVA/Borax/ Xylan/Zn(OTf) 2 ) with OH-rich xylan to tackle these problems. The resultant PBXHE, dually cross-linked chemically and physically, showcases mechanical robustness. The incorporated xylan polysaccharide facilitates the formation of a well-developed interconnected porous network within the hydrogel, promoting electrolyte ion mobility. Concurrently, the coordinated interaction between the polar hydroxyl groups in xylan and polyvinyl alcohol (PVA) induces the uniform deposition of zinc ions. Therefore, the symmetric Zn|PBXHE|Zn cell exhibits remarkable durability, operating continuously for 520 h at 1 mA cm −2 and accumulating a total capacity of 3000 mA h cm −2 at 20 mA cm −2 . The as-fabricated hydrogel-based zinc-ion hybrid capacitor retains almost 90% of its initial capacity after 20,000 cycles, with a peak energy density of 82.1 W h kg −1 at 193.7 W kg −1 power density. This work provides a feasible strategy for engineering environmentally benign polysaccharide-assisted hydrogel electrolytes to protect Zn anodes for the sustainable development of competitive Zn-based energy storage devices.

Triple-Responsive, Multimodal, Visual Electronic Skin toward All-in-One Health Management for Gestational Diabetes Mellitus

“…It was found in SEM (Figure j) that the pore size of the PVA-B hydrogel was large, so the toughness and strength of the hydrogel were hard to be obtained . The addition of cellulose ether enhanced the hydrogen bond, made the pore structure more uniform (Figures l 1 and l 2 ), and improved the mechanical properties of the hydrogel.…”

“…The addition of cellulose ether enhanced the hydrogen bond, made the pore structure more uniform (Figures l 1 and l 2 ), and improved the mechanical properties of the hydrogel. Element mapping of EDS (Figure k) shows that C, O, Na, and B elements were evenly distributed in the hydrogel without phase separation, confirming that a uniform dispersed hydrogel was synthesized, which contributes to the mechanical properties and stability of the hydrogel …”

“…Furthermore, the chemical structure of the hydrogel was further analyzed by XPS (Figure b). The binding energies of C 1s are 283.9, 285.2, and 287 eV, respectively, which are attributed to C–C/C–H, C–O, and C–O–B in the PVA-B hydrogel . The C–O binding energy of the PB-MC hydrogel was enhanced and shifted to 285.4 eV, indicating that a strong hydrogen bond was formed between PVA and MC, which was consistent with the conclusion of FTIR.…”

“…Two distinguishable peaks, B–O–C (191.2 eV) and B–O–B (190.4 eV), were generated by splitting the B 1s spectrum. This indicates the hydrogel network was constructed based on borate ester bonds and hydrogen bonds …”

3D-Polyacrylamide/Ti-MXene: A Newer Hybrid Hydrogel Electrolyte Featuring High Mechanical Strength and Durability for Flexible Aqueous Zinc-Ion Batteries

“…The asymmetric cell runs steadily for more than 400 cycles with an average Coulombic efficiency (CE) of 98.4% (Figure c), which is purely attributed to the ultrastable PAM/Ti-MXene (0.1 wt %) HHGE and the compatible electrode–electrolyte interface. Notably, the 2 M ZnSO 4 liquid electrolyte results in poor reversibility for the Zn//Cu asymmetric cell, leading to short-circuiting around 60–90 cycles. EIS is performed for a fresh cycle, and after 100 cycles, it exhibits a low interfacial resistance, which is highly optimum for the Zn anode and is capable of building good interfacial compatibility between PAM/Ti-MXene (0.1 wt %) HHGE and the Zn anode (Figure S9).…”