A-site deficient perovskite lithium praseodymium titanate as a high-rate anode for lithium-ion batteries

Abstract

On account of the low operating potential and slow electrochemical kinetics, graphite anode suffers from poor rate performance and severe safety problems in lithium-ion batteries (LIBs). Therefore, it’s urgent to find alternatives. Due to the abundant intrinsic vacancies and ion migration channels, A-site deficient perovskites could be used as not only solid state electrolytes (SSEs), but also anodes for LIBs. Here, Li0.38Pr0.54TiO3 is firstly demonstrated as a high-rate anode material without any additional modification. With an average operating potential of 0.76 V vs. Li+/Li, the Li0.38Pr0.54TiO3 anode possesses a high specific capacity of 217 mAh g−1 at 0.1C (1C = 200 mA g−1), impressive rate capability (124 mAh g−1 at 40C), and excellent cycling performance (96.75 % capacity retention over 2100 cycles at 10C). Through in-situ analysis and theoretical computations, we confirm the outstanding performance originates from small cell volume change (5.98 %), low band gap (2.57 eV), and low diffusion energy barrier (0.11 eV). The LiFePO4//Li0.38Pr0.54TiO3 full cell shows superior cycling stability (79.78 % capacity retention over 1000 cycles at 5C). Moreover, the relationship between A-site structure and electrochemical properties is discussed from the perspective of vacancy concentration. Our finding also provides a novel perspective for the discovery of high-performance oxide perovskite anodes.