Enhanced low-temperature performance of multiscale (Nb2O5/TiNb2O7)@C nanoarchitectures with intensified ion diffusion kinetics

Abstract

Since the performance of commercial graphite anodes for lithium-ion batteries declines significantly at low temperatures, it is significant to pursue novel materials with augmented charge storage ability. Herein, a multiscale (Nb2O5/TiNb2O7)@C nanoarchitecture is designed to satisfy the requirements of low-temperature environments. The unique nanoarchitecture morphology, surface carbon layer coating, and dual-phase structure can lead to short transport paths, favorable conductivity, and abundant grain boundaries, resulting in enhanced ion diffusion kinetics. Specifically, (Nb2O5/TiNb2O7)@C anode exhibits a significantly increased Li+ diffusion coefficient of 1.26 × 10−11 cm2 s−1. Then, a reversible capacity of 184 mAh g−1 (@1.0C) is achieved after 200 cycles at room temperature, while it can maintain 110 mAh g−1 (@0.1C) after 80 cycles at −40 °C, equivalent to 40 % of its room temperature capacity (272.4 mAh g−1, 0.1C). This work provides a multiscale modification strategy to develop novel nanoarchitectures with enhanced ion/electron diffusion kinetics for low-temperature applications.