Rationally Designed Metal Sulfide-LDH Heterostructures for High Energy Aqueous Zn-Based Battery Cathodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rechargeable alkaline Zn-Ni(Co) batteries have high voltage and safety but suffer from slow cathode reactions and side reactions.
• These issues limit the energy density and power capability of existing Zn-Ni batteries.

Purpose of the Study:

• To design and synthesize a novel crystalline-amorphous heterostructure cathode for improved Zn-Ni battery performance.
• To address the limitations of sluggish kinetics and parasitic reactions in aqueous Zn-based batteries.

Main Methods:

• Synthesized a heterostructure cathode combining mixed Ni and Co sulfides (MS) with Ni-Co layered double hydroxides (LDHs).
• Fabricated an aqueous Zn@CP||MS-LDH battery using a gel-coated Zn anode (Zn@CP).
• Characterized the electrochemical performance, including specific capacity, energy density, and power density.

Main Results:

• The engineered MS-LDH cathode exhibited abundant active sites, improved ion adsorption, and faster ion diffusion.
• The battery achieved a high specific capacity of 773 mAh g^-1 at 2 A g^-1.
• The aqueous Zn@CP||MS-LDH battery delivered an ultrahigh specific energy of 1309 Wh kg^-1 and a specific power of 3.44 kW kg^-1, with excellent rate capability and cycling stability.

Conclusions:

• The crystalline-amorphous heterostructure design synergistically enhances electrochemical performance.
• Earth-abundant heterostructured materials show significant promise for overcoming limitations in aqueous Zn-based batteries.
• This work presents a viable pathway toward sustainable and high-performance energy storage technologies.