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

Abstract

Lithium-rich manganese-based cathode materials Li[Li x Ni y Mn 1-x- y ]O 2 have received considerable attention. However, severe voltage decay and structural distortion of O3-type layered oxides hinder further practical application. O2-type layered cathode materials can restrict the movements of transition metals and effectively suppress the voltage decay. However, O2-type layered oxides are fundamentally limited by inferior rate performance. Herein, we introduce cobalt into the TM layer in the O2-type oxide, Li 0.80 [Ni 0.25 Mn 0.66 Co 0.02 □ 0.07 ]O 2 (□ represents vacancy, O2-LNMCO), which increases electronic and ionic conductivity, improving Li + diffusion kinetics. Significantly, O2-LNMCO displays excellent rate property, delivering a discharge specific capacity of 145 mAh g -1 at 5 C and 111.6 mAh g -1 at 10 C. Furthermore, the voltage decay of O2-LNMCO was restrained with attenuation rate of 2.23 mV per cycle.