Creatinine: A Muscle Metabolite as a Multifunctional Electrolyte Additive for Aqueous Zinc-Ion Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) offer sustainable, safe, and cost-effective energy storage.
• Zinc dendrite growth and side reactions limit AZIBs' practical application and cycling stability.

Purpose of the Study:

• To investigate creatinine (Cre) as a multifunctional electrolyte additive for enhancing AZIB performance.
• To elucidate the mechanisms by which Cre improves Zn anode stability and cycling.

Main Methods:

• Experimental analysis of AZIBs with creatinine additive.
• Theoretical calculations to understand Cre's interaction with Zn2+ and the electric double layer.
• Fabrication and testing of Zn||Zn symmetric cells and Zn||VO2 full cells.

Main Results:

• Creatinine disrupts Zn2+ solvation structure and forms a water-deficient electric double layer.
• Cre promotes uniform Zn deposition on (002) planes, suppressing dendrite formation.
• Zn||Zn symmetric cells with Cre additive achieved 900h stable cycling (11-fold increase).
• Zn||VO2 full cells showed ~105 mAh g-1 capacity retention after 300 cycles at 10 C.

Conclusions:

• Creatinine is an effective multifunctional additive for improving AZIB performance.
• Cre enhances Zn anode stability by controlling solvation, interfacial reactions, and deposition.
• The findings pave the way for more durable and efficient AZIBs for grid-scale energy storage.