Tuning the rate performance in O2-type layered manganese-based oxides through cobalt doping

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-rich manganese-based cathode materials (Li[Li_xNi_yMn_1-x-y]O₂) are promising for batteries.
• O3-type oxides suffer from voltage decay and structural instability.
• O2-type oxides offer better structural stability but have poor rate performance.

Purpose of the Study:

• To enhance the rate performance and suppress voltage decay of O2-type layered cathode materials.
• To investigate the effect of cobalt doping on the electrochemical properties of O2-type oxides.
• To develop a novel cathode material for improved lithium-ion battery applications.

Main Methods:

• Synthesis of cobalt-doped O2-type oxide: Li_0.80[Ni_0.25Mn_0.66Co_0.02□_0.07]O₂ (O2-LNMCO).
• Electrochemical characterization including rate capability tests and cycling stability analysis.
• Analysis of structural and electronic properties to understand performance improvements.

Main Results:

• Cobalt introduction into the transition metal layer improved electronic and ionic conductivity.
• O2-LNMCO exhibited excellent rate properties, delivering 145 mAh g^-1 at 5 C and 111.6 mAh g^-1 at 10 C.
• Voltage decay was significantly restrained, with an attenuation rate of only 2.23 mV per cycle.

Conclusions:

• Cobalt doping is an effective strategy to overcome the rate limitations of O2-type layered cathode materials.
• The developed O2-LNMCO material shows potential for high-performance lithium-ion batteries.
• This research contributes to the advancement of stable and high-capacity cathode materials for energy storage.