Highly Reversible Li-Se Batteries with Ultra-Lightweight N,S-Codoped Graphene Blocking Layer

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High energy density rechargeable lithium batteries are crucial for practical applications.
• Developing advanced electrode materials is key to improving battery performance.

Purpose of the Study:

• To synthesize a novel, binder-free nitrogen and sulfur codoped graphene (N,S-G) blocking layer.
• To evaluate the performance of N,S-G in lithium-selenium (Li-Se) batteries.

Main Methods:

• Vacuum filtration method for synthesizing the N,S-G membrane.
• Integration of the N,S-G membrane as a blocking layer in Li-Se batteries.

Main Results:

• The N,S-G membrane is ultra-lightweight, conductive, and freestanding.
• Li-Se batteries with N,S-G achieved high reversible discharge capacity (330.7 mAh g⁻¹ at 1 C after 500 cycles).
• Excellent rate performance (over 310 mAh g⁻¹ at 4 C) was observed with high active material loading (~5 mg cm⁻²).

Conclusions:

• The enhanced performance is attributed to homogenous dispersion, good Li⁺-ion conductivity, fast electron transport, and polyselenide confinement.
• N,S-G is a promising strategy for increasing the energy density of Li-Se batteries.
• Heteroatom doping of carbon matrices offers a viable route for advanced Li-Se battery development.