Bio-Inspired Polyanionic Electrolytes for Highly Stable Zinc-Ion Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Non-uniform zinc plating/stripping in zinc-ion batteries (ZIBs) leads to high polarization and low Coulombic efficiency (CE), limiting their large-scale application.
• Developing stable and efficient anodes is crucial for advancing ZIB technology.

Purpose of the Study:

• To develop a high-performance solid electrolyte interphase (SEI) layer for zinc anodes in ZIBs.
• To improve the uniformity of zinc plating/stripping and enhance the overall battery performance.

Main Methods:

• Utilizing anionic polyelectrolyte alginate acid (SA) for in situ SEI formation on the zinc anode.
• Investigating the effect of SA on Zn2+ ion affinity, desolvation structure, and nucleation energy.
• Assembling Zn||Cu cells and pouch cells to evaluate electrochemical performance, including CE and capacity retention.

Main Results:

• SA coating induced a well-aligned channel for uniform zinc plating due to the affinity of Zn2+ ions to alginate acid's anionic groups.
• The SEI layer regulated Zn2+ desolvation and promoted the formation of compact Zn (002) crystal planes.
• SA-coated Zn anodes exhibited stable stripping/plating with low potential difference (0.114 V) even at high depth of discharge (DOD).
• Nucleation energy for SA-coated Zn was reduced by 97%, leading to a faster nucleation rate.
• Zn||Cu cells achieved an average CE of 99.8% over 1,400 cycles.
• Pouch cells with SA-coated Zn anodes showed 96.9% capacity retention compared to 59.1% for bare Zn anodes under high cathode mass loading.

Conclusions:

• Alginate acid is an effective material for creating a high-performance SEI layer on zinc anodes in ZIBs.
• The SA-induced SEI layer significantly enhances the stability and Coulombic efficiency of ZIBs.
• This biomass-inspired strategy offers a promising pathway for the practical application of high-performance ZIBs.