Synergetic effect of lattice distortion and oxygen vacancies on high-rate lithium-ion storage in high-entropy perovskite oxides

Abstract

High-entropy oxides (HEOs) have gained great attention as an emerging kind of highperformance anode materials for lithium-ion batteries (LIBs) due to the entropy stabilization and multi-principal synergistic effect. Herein, the porous perovskite-type RE(Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)O3 (RE (= La, Sm, and Gd) is the abbreviation of rare earth) HEOs were successfully synthesized by a solution combustion synthesis (SCS) method. Owing to the synergistic effect of lattice distortion and oxygen vacancies (OV), the Gd(Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)O3 electrode exhibits superior high-rate lithium-ion storage performance and excellent cycling stability. A reversible capacity of 403 mAh·g–1 at a current rate of 0.2 A·g–1 after 500 cycles and a superior high-rate capacity of 394 mAh·g−1 even at 1.0 A·g–1 after 500 cycles are achieved. Meanwhile, the Gd(Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)O3 electrode also exhibits a pronounced pseudo-capacitive behavior, contributing to an additional capacity. By adjusting and balancing the lattice distortion and oxygen vacancies of the electrode materials, the lithium-ion storage performance can be further regulated.