Li3BO3 decoration endows fast reaction kinetics of LiFePO4 cathode for lithium ion batteries

Olivine-type lithium iron phosphate is widely used as a cathode material for lithium-ion batteries because of its moderate operating voltage, excellent stability, and high safety. However, the high rate capability of LiFePO 4 is limited by its low electrical conductivity. Additionally, its interface and internal structure would degrade under high-rate conditions. To address these issues, Li 3 BO 3 was prepared via sol-gel method as the surface decoration to enhance the rate performance of LiFePO 4 . The Li 3 BO 3 decorated LiFePO 4 (B-LiFePO 4 ) maintains the structural integrity during cycling under large current densities, furthermore, it induces the formation of favorable cathode-electrolyte interface (CEI) with less Li 2 CO 3 and more Li 2 O contents, and reduces the activation energy of Li + diffusion in the CEI layer and charge transfer, thus the high capacity and long cycle performances of LiFePO 4 are achieved when cycled at high current densities. At ambient environment and 30C, B-LiFePO 4 delivers a high reversible capacity of 63.1 mAh g −1 , and a capacity retention of 90 % can be realized over 600 cycles at 1C. In contrast, the original LiFePO 4 delivers only 27.8 mAh g −1 at 30C and a capacity retention of 67.2 % after 600 cycles at 1C. Besides, B-LiFePO 4 demonstrates good low temperature performance, it exhibits high capacities of 122.1 and 80.7 mAh g −1 at 1C, 0 °C and − 20 °C, respectively. This study provides a simple method to enhance the reaction kinetics of LiFePO 4 cathode, which would benefit the development of LiFePO 4 based lithium ion batteries with high rate performance. • Li 3 BO 3 decorated LiFePO 4 presents superior rate performance even up to 30C and better low-temperature performance. • The Li 3 BO 3 decorated LiFePO 4 shows enhanced structure stability during cycling, in comparison to the original LiFePO 4 . • Favorable CEI film is formed for Li 3 BO 3 decorated LiFePO 4 , which enhances the reaction kinetics and structural stability.