Cation-in-Mesopore Complex for 20 Ah-Level Aqueous Battery.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Metallic Zn-based aqueous batteries (ZABs) offer safe energy storage but face challenges with side reactions and dendrite growth, limiting practical applications, especially at the Ah-level.
• Developing stable and high-performance ZABs is crucial for next-generation energy storage solutions.

Purpose of the Study:

• To introduce a novel cation-in-mesopore (CiM) complex chemistry for constructing high-capacity ZABs.
• To address the limitations of dendrite proliferation and side reactions in metallic Zn anodes.

Main Methods:

• Utilized molecule dynamics and X-ray absorption near-edge structure (XANES) analyses to investigate Zn2+ confinement within single-mesopore SiO2 (smSiO2).
• Employed in situ electrochemical digital holography, in situ interface Fourier-transform infrared spectroscopy, and H-bonds density analyses to study interfacial mechanisms.
• Constructed and tested 20 Ah-level Zn//VO2 pouch batteries.

Main Results:

• The smSiO2 effectively traps Zn2+, forming Zn2+-smSiO2 complexes that migrate to the Zn anode.
• These complexes facilitate the formation of a stable interface, disrupting water aggregation and suppressing H2O degradation and dendrite growth.
• The Zn anode demonstrated stable cycling over 800 hours at 55% depth of discharge.
• The 20 Ah-level Zn//VO2 pouch battery achieved capacities of 20.5 Ah at 0.2 A g-1 and 8.59 Ah at 1 A g-1, with energy densities of 65 Wh kg-1 and 96 Wh L-1.

Conclusions:

• The proposed cation-in-mesopore complex chemistry provides a new paradigm for developing stable and high-performance Ah-level ZABs.
• This approach effectively mitigates critical issues in Zn anodes, paving the way for more sustainable and reliable energy storage.
• The findings represent a significant advancement in the field of aqueous batteries.