Low-Temperature and High-Performance Vanadium-Based Aqueous Zinc-Ion Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) offer safe and cost-effective energy storage but suffer from poor low-temperature performance, including dendrite growth and capacity fade.
• Low temperatures exacerbate issues like lattice contraction, slow charge transfer, and solid-phase diffusion, hindering AZIB functionality and limiting their practical application.

Purpose of the Study:

• To develop a high-performance AZIB system capable of stable operation at low temperatures.
• To address critical challenges such as dendrite formation, cathodic dissolution, and capacity degradation in sub-zero environments.

Main Methods:

• Utilized manganese vanadate (MVO) as a cathode material for enhanced structural stability and specific capacity.
• Incorporated ethylene glycol (EG) and manganese sulfate (MSO) as electrolyte additives to mitigate freezing point and promote ion desolvation.
• Investigated the synergistic effects of MVO, MSO, and EG on zinc anode protection and cathode stability at low temperatures.

Main Results:

• The developed EG@0.2 M MnSO₄ + 2 M ZnSO₄ electrolyte enabled stable Zn||Zn battery operation for 350 hours at -30 °C and 1 mA cm^-2.
• Zn||Cu cells demonstrated 100% Coulombic efficiency over 2000 cycles at 0.2 mA cm^-2.
• The Zn||MVO battery achieved an initial specific capacity of 231.13 mA h g^-1 with over 85% retention after 1000 cycles, outperforming existing low-temperature AZIB systems.

Conclusions:

• The synergistic combination of MVO cathode, Mn²⁺ cationic shield from MSO, and EG-based electrolyte effectively suppresses dendrite growth and enhances low-temperature performance.
• This novel electrolyte formulation provides a promising solution for reliable and high-capacity aqueous zinc-ion batteries operating in cold environments.