A Long Cycle-Life High-Voltage Spinel Lithium-Ion Battery Electrode Achieved by Site-Selective Doping

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Spinel lithium nickel manganese oxide (LiNi0.5Mn1.5O4, LNMO) is a key cathode material for high energy-density lithium-ion batteries (LIBs).
• Poor cycle stability currently limits the practical application of LNMO in LIBs.
• Structural degradation and manganese dissolution are major challenges affecting LNMO performance.

Purpose of the Study:

• To enhance the cycle stability and durability of LNMO cathodes through site-selective atomic doping.
• To investigate the effects of magnesium (Mg) doping on the structural and electrochemical properties of LNMO.
• To demonstrate the potential of Mg-doped LNMO in advanced LIBs.

Main Methods:

• Site-selective doping of Mg onto tetrahedral (8a) and octahedral (16c) sites within the Fd-3m spinel structure of LNMO.
• Electrochemical characterization of Mg-doped LNMO in half-cells and prototype full-batteries.
• Analysis of structural stability and mitigation of manganese dissolution.

Main Results:

• Mg doping successfully stabilized the LNMO structure, suppressing detrimental two-phase reactions.
• Site-selective doping mitigated manganese dissolution during electrochemical cycling.
• Mg-doped LNMO electrodes demonstrated exceptional cycle stability and durable electrochemical performance.
• Successful integration with TiNb2O7 counter-electrodes in prototype full-batteries.

Conclusions:

• Site-selective Mg doping is an effective strategy to improve the structural integrity and electrochemical stability of LNMO cathodes.
• This atomic engineering approach offers a pathway to overcome performance limitations in high-energy-density LIBs.
• The developed doping strategy can be extended to other electrode materials for advanced energy storage devices.