Low-Temperature Synthesis of Lithium Lanthanum Titanate/Carbon Nanowires for Fast-Charging Li-Ion Batteries

Due to the lower working voltage and higher capacity, the Li-rich lithium lanthanum titanate perovskite (LLTO) anode is becoming a potential candidate for the commercial Li4Ti5O12 (LTO) Li-ion battery anode [Zhang, L.et al. Lithium Lanthanum Titanate Perovskite as an Anode for Lithium Ion Batteries. Nat. Commun. 2020, 11, 3490]. However, a high temperature of 1250 degrees C is required to fabricate pure LLTO particles by the conventional solid-phase calcination method, limiting their further practical applications. Here, an in situ carbon nanospace confined method is developed to synthesize the pure LLTO with subnanometer grain size at an extremely low temperature of 800 degrees C. The LLTO precursor is confined in the in situ formed carbon nanowire matrix during heating, resulting in a shorter solid-phase diffusion distance and subsequently lower energy required for the formation of the pure LLTO phase. The low-temperature-synthesized pure LLTO/carbon composite nanowires (P-LLTO/C NWs) exhibit improved lithium storage performances than the traditionally prepared LLTO due to the fast electronic conduction of carbon and the stable carbon surface. In addition, the working potentials of P-LLTO/C parallel to LiFePO4 and P-LLTO/C parallel to LiCoO2 full cells are all 0.7 V higher than that of the corresponding commercial full cells with LTO as an anode, meaning much higher power energy densities (307.6 W kg(-1) at 2C and 342.4 W kg(-1) at 1C vs 198.4 W kg(-1) and 275.2 W kg(-1) for LTO parallel to LiFePO4 and LTO parallel to LiCoO2 full cells based on electrode materials, respectively). This low-temperature synthesis method can extend to other solid-state ionic materials and electrode materials for electrochemical devices.