A Versatile Carbon Nanotube-Based Scalable Approach for Improving Interfaces in Li-Ion Battery Electrodes

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Resistive interfaces at the current collector-active material interface (CCAMI) limit energy and power densities in lithium-ion batteries (LIBs).
• Current methods involve mixing active materials with conductive additives in organic solvents, posing environmental concerns and not fully addressing CCAMI resistance.

Purpose of the Study:

• To investigate the effectiveness of carbon nanotubes (CNTs) in reducing CCAMI resistance for LIBs.
• To explore the potential of CNTs to enable eco-friendly aqueous processing of battery electrodes.
• To enhance the energy and power densities of LIBs using CNT-modified current collectors.

Main Methods:

• Direct growth or spray-coating of CNTs onto aluminum (Al) foil current collectors.
• Fabrication of electrodes using LiFePO4 (LFP) and LiNi0.33Co0.33Mn0.33O2 (NMC) cathode materials with CNT-coated Al foils.
• Electrochemical testing of LIBs to evaluate energy density, power density, and cycling stability.

Main Results:

• CNT coatings significantly reduced CCAMI resistance for both LFP and NMC cathode materials.
• Vertically aligned CNT coatings on Al foils yielded high energy densities: ~500 Wh kg-1 for LFP and ~760 Wh kg-1 for NMC.
• CNT-modified electrodes demonstrated superior cycling stability, withstanding 600 mA g-1 for 500 cycles (LFP), outperforming commercial electrodes.
• CNT coatings facilitated aqueous processing, eliminating the need for toxic organic solvents.

Conclusions:

• CNT-based CCAMI engineering is a versatile and effective strategy to enhance LIB performance.
• This approach offers a pathway to higher energy and power densities while promoting environmentally friendly manufacturing processes.
• The CNT-based CCAMI modification shows broad applicability for improving both cathode and anode materials in LIBs.