Single-Crystal-like Durable LiNiO₂ Positive Electrode Materials for Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Cobalt-free, nickel-rich positive electrode materials like LiNiO2 (LNO) offer high energy density and low cost.
• Poor cycling performance remains a key challenge for LNO materials, necessitating improved stability.

Purpose of the Study:

• To investigate the electrochemical properties and cycling performance of single-crystal-like LNO (SC-LNO) compared to polycrystalline LNO (PC-LNO).
• To demonstrate the enhanced stability and durability of SC-LNO for advanced battery applications.

Main Methods:

• Fabrication of SC-LNO and PC-LNO samples.
• Electrochemical characterization including long-term cycling tests (500 cycles) at 2C rate and 45 °C.
• Post-mortem analysis using electron backscattering diffraction and microscopy to assess particle integrity and surface changes.

Main Results:

• SC-LNO exhibited significantly better capacity retention (63.5%) after 500 cycles compared to PC-LNO (36.1%).
• SC-LNO maintained a stable dQ/dV profile and showed no particle cracking, unlike PC-LNO which degraded significantly.
• PC-LNO experienced greater impedance increase due to rock-salt phase formation and interface cracking, while SC-LNO showed less degradation.

Conclusions:

• Single-crystal-like LNO particles offer superior structural and electrochemical stability, leading to improved cycling performance.
• The fabrication of SC-LNO is a promising strategy to overcome the limitations of polycrystalline nickel-rich cathode materials.
• Single-crystal-like morphology is critical for developing durable, high-energy density battery electrodes.