Pretreated precursor to realize dual modification that improves the high voltage electrochemical performance of LiNi0.8Co0.1Mn0.1O2 cathode materials

Ni-rich cathodes have been increasingly studied due to their satisfactory capacity and low cost. However, the rapid attenuation of capacity during charging and discharging Ni-rich cathodes limits their practical use. In this work, a KMnO 4 -pretreated precursor is used to synthesize LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) in air. The product shows various morphological and structural characterizations, thereby verifying that the pretreatment can successfully achieve the dual modification of a MnO 2 coating and Mn 4+ doping. Electrochemical tests indicate that the 1.0 wt% KMnO 4 -pretreated sample exhibits superior cycling performance from 3.0 to 4.5 V. Additionally, the capacity retention rate after 100 cycles reaches 79.15% at 0.2 C, which shows that the pretreated sample has better cycling stability compared with the pure sample calcined in air (59.22%) and the pure sample calcined in oxygen (71.17%). In addition, the capacity retention reaches 82.27% at a high current density of 1 C while suppressing the potential polarization. Cyclic voltammetry and electrochemical impedance spectroscopy tests show that the pretreatment decreases the resistance and suppresses the irreversible phase transition. The protective MnO 2 coating inhibits the interfacial reactions between the active substance and electrolyte, while the Mn 4+ dopant improves the crystal structure. Therefore, it is concluded that LiNi 0.8 Co 0.1 Mn 0.1 O 2 , with a superior electrochemical performance at a high of 4.5 V, can be prepared through a KMnO 4 -pretreated precursor in air.