An iron oxyborate Fe3BO5 material as a high-performance anode for lithium-ion and sodium-ion batteries

Abstract

An Fe₃BO₅ anode material synthesized by reducing Fe₃BO₆ was comprehensively studied for use in both lithium- and sodium-ion batteries. As a lithium-ion battery anode, the obtained Fe₃BO₅ displays a high initial reversible capacity of 654.7 mA h g⁻¹ (with a coulombic efficiency of 75%) at a current density of 0.1 A g⁻¹ and a favorable cycling performance, with a capacity of 544.6 mA h g⁻¹ at 0.4 A g⁻¹ after 400 cycles. As a sodium-ion battery anode, Fe₃BO₅ displays initial discharge/charge capacities of 644.6 and 433.6 mA h g⁻¹ at a current density of 0.1 A g⁻¹. Besides this, Fe₃BO₅ exhibits a stable reversible capacity of about 380 mA h g⁻¹ at 0.4 A g⁻¹ during the first 100 cycles and an excellent rate performance with a high capacity of 304.5 mA h g⁻¹, even at a current density of as large as 4 A g⁻¹. Kinetics analysis shows that the significance in high Na⁺ capacitive contribution at a high rate should account for the excellent rate performance. The excellent electrochemical properties demonstrate that the Fe₃BO₅ material could be an effective and promising anode candidate for both lithium- and sodium-ion batteries.