Self-Healable Hydrogel Electrolyte toward High-Performance and Reliable Quasi-Solid-State Zn–MnO₂ Batteries

Abstract

Zinc-ion batteries are promising power sources, but their practical application is impeded by the Zn dendrite growth and side reactions at the electrode/electrolyte interface. Here, we report that such issues can be effectively addressed by a self-healable hydrogel electrolyte. The electrolyte is comprised of carboxyl-modified poly­(vinyl alcohol) cross-linked by COO–Fe bonding in the presence of Zn­(NO3)2 and MnSO4. A quasi-solid-state Zn–MnO2 battery using the electrolyte delivers a specific capacity up to 177 mAh g–1 after 1000 cycles with a retention rate of 83%, which is much better than its equivalent using an aqueous electrolyte. The improvement is attributed to efficient suppression of the dendrite growth and side reactions at the electrode/electrolyte by the hydrogel electrolyte. More importantly, the battery autonomously recovery its energy-storage functions even after multiple physical damages, showing excellent robustness and reliability. The present investigation provides an effective strategy to address the energy-storage performance and reliability of a light-metal battery system.

A Self‐Healing Flexible Quasi‐Solid Zinc‐Ion Battery Using All‐In‐One Electrodes

“…The self-healing mechanism of the hydrogel was ascribed to the COO-Fe bonds. [12] Ma et al reported an all-solid-state Zn-ion battery in which poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and poly(ethylene oxide) (PEO) co-polymer provided hydrogen bonds to enhance the flexibility. [13] As seen from these achievements, it is promising to construct a high-performance self-healing flexible Zn-ion battery by using hydrogel electrolyte and all-in-one 3D electrodes, which have been rarely studied.…”

Recent progress of flexible aqueous multivalent ion batteries

“…Li et al observed the self-healing process of a cut PVA-based hydrogel electrolyte by optical microscopy. 103 Surprisingly, it showed nearly no scars at the contact interface after 10 min of self-healing (Figure 8A), proving the structural integrity of the self-healed hydrogel. The ion conductivity of self-healing hydrogels can usually be recovered after self-healing (Figure 8B), whereas irreversible damage of mechanical strength tended to occur after a few self-healing cycles (Figure 8B,C 29 ).…”

Current Advances on Zn Anodes for Aqueous Zinc‐Ion Batteries

“…Here their effects on Zn deposition are discussed. In Zn(NO 3 ) 2 ‐MnSO 4 ‐poly(vinyl alcohol) cross‐linked by COO‐Fe, a porous surface of the cycled Zn can be formed without dendrite, compared with dendrites formed in its aqueous counterpart [34] . The resulted morphology is associated with the regulation between COOH and Zn 2+ at the interface.…”