Boosting high-rate Li-ion storage properties by La(III) ion doping in spinel (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4 high-entropy oxide anode

The present work aims to create lattice distortion and optimize the surface oxygen vacancy (O V ) concentration in a model spinel (Co 0.2 Cr 0.2 Fe 0.2 Mn 0.2 Ni 0.2 ) 3 O 4 high-entropy oxide (HEO) through a heteroatom La 3+ doping strategy. As demonstrated, La 3+ with a large radius can be doped successfully into the spinel lattice of (Co 0.2 Cr 0.2 Fe 0.2 Mn 0.2 Ni 0.2 ) 3 O 4 , thereby not only causing lattice distortion to increase oxygen vacancies but also refining crystalline grains and improving the specific area. Compared with the (Co 0.2 Cr 0.2 Fe 0.2 Mn 0.2 Ni 0.2 ) 3 O 4 anode, the (La 0.01 CoCrFeMnNi) 3/5.01 O 4 anode with moderate doping exhibits excellent cycling performance (1228 mAh<middle dot>g -1 after 400 cycles at 0.2 A<middle dot>g -1 ) and yields an increase of 75% rate capability at 3 A<middle dot>g -1 (420 mAh<middle dot>g -1 at 3 A<middle dot>g -1 ). The desirable kinetic transport of electrons and diffusion of Li + within the moderately La 3+-doped anode and the synergistic interfacial pseudocapacitive behavior satisfy the redox reaction at a high rate, thus increasing rate capability.