High-rate electrochemical lithium-ion storage through Li+ intercalation pseudocapacitance in the Pr1/3NbO3 anode

Abstract

Pseudocapacitance is commonly associated with surface or near-surface redox reaction inside electrode materials, which holds the key to improving the rate capability. However, challenges arise due to the unsatisfactory Li⁺/electron transport and microstructure of most electrode materials. Here, we exploit conductive Pr_1/3NbO₃ with ultra-high Li⁺ intercalation pseudocapacitance, which is a promising alternative for fast-charging LIBs. The micro-sized Pr_1/3NbO₃ presents a large capacity of 161.9 mA h g⁻¹ at a high current rate of 10C, which is higher than those of most reported fast-charging electrode materials, indicating its excellent rate capability (10C vs. 0.1C capacity ratio of 73.1%). The excellent rate capability can be attributed to the ultra-high Li⁺ intercalation pseudocapacitance of Pr_1/3NbO₃, which originates from the fast electron/ion transport and the open three-dimensional ion transport network. Additionally, Pr_1/3NbO₃ exhibits superior cycling stability with a high capacity retention of 99.7%/97.4% after 250/3000 cycles at 1C/10C. The exceptional cycling stability of Pr_1/3NbO₃ is likely to be a result of a typical low-strain characteristic, where the volume variation of the unit cell was determined to be only 2.21% during electrochemical cycling. Therefore, Pr_1/3NbO₃ holds great promise for fast- and stable-charging applications in LIBs.