NiSO4·6H2O, MnSO4·H2O, and CoSO4·7H2O (Beijing
Chemical Factory, China) were first mixed, and an aqueous
solution with a concentration of 2.0 mol L–1 MSO4 (M = Ni, Mn, Co) was achieved. The solution was pumped into
a continuously stirred tank reactor (CSTR, 2.0 L) under the N2 atmosphere. At the same time, NaOH solution (10.0 mol L–1) and NH3·H2O solution
(10.0 mol L–1, Beijing Chemical Factory, China)
were fed into the CSTR separately, where the ratio of NH3/MSO4 was controlled strictly at 0.8. The pH value (11.00
± 0.05), temperature (60 °C), and stirring speed (1000 rpm)
were monitored and controlled carefully during the reaction process.
When the coprecipitation reaction was done, the suspension was filtered,
washed, and finally dried at 120 °C for 12 h. The as-obtained
Ni0.6Co0.2Mn0.2(OH)2 powder
was mixed thoroughly with LiOH·H2O (Beijing Chemical
Factory, China) at a molar ratio of 1:1.05. The mixture was sintered
at 500 °C for 5 h and 875 °C for 12 h in the air at a rising
rate of 1 °C min–1. Afterward, the product
was slowly cooled down to 800 °C for another 5 h and then to
500 °C under a rate of 1 °C min–1.
Chemical Factory, China) were first mixed, and an aqueous
solution with a concentration of 2.0 mol L–1 MSO4 (M = Ni, Mn, Co) was achieved. The solution was pumped into
a continuously stirred tank reactor (CSTR, 2.0 L) under the N2 atmosphere. At the same time, NaOH solution (10.0 mol L–1) and NH3·H2O solution
(10.0 mol L–1, Beijing Chemical Factory, China)
were fed into the CSTR separately, where the ratio of NH3/MSO4 was controlled strictly at 0.8. The pH value (11.00
± 0.05), temperature (60 °C), and stirring speed (1000 rpm)
were monitored and controlled carefully during the reaction process.
When the coprecipitation reaction was done, the suspension was filtered,
washed, and finally dried at 120 °C for 12 h. The as-obtained
Ni0.6Co0.2Mn0.2(OH)2 powder
was mixed thoroughly with LiOH·H2O (Beijing Chemical
Factory, China) at a molar ratio of 1:1.05. The mixture was sintered
at 500 °C for 5 h and 875 °C for 12 h in the air at a rising
rate of 1 °C min–1. Afterward, the product
was slowly cooled down to 800 °C for another 5 h and then to
500 °C under a rate of 1 °C min–1.