Ionic-conductive sodium titanate to boost sodium-ion transport kinetics of hard carbon anode in sodium-ion batteries

Abstract

Hard carbon with abundant resources, low-cost, and high specific capacity, is a promising anode material for large-scale sodium-ion batteries. However, the poor rate performance of hard carbon suffers from serious challenges due to sluggish ion transport dynamic behavior, especially at low potential, in high power density of sodium-ion batteries. To address this issue, we introduce an ionic-conductive sodium-titanate into hard carbon to boost its sodium-ion transport kinetics via constructing a dual ionic-electronic conducting network in hard carbon anode. Benefiting from our design, the optimized hard carbon-sodium titanate electrode achieves high specific capacity of 137 mAh g−1 at a high current density of 10 A g−1, compared to that of hard carbon of 25 mAh g−1 at 10 A g−1. Remarkably, it also exhibits an excellent capacity retention of 71.4% at the current density of 2.0 A g−1 after 800 cycles. This work presents a practical strategy for high-rate hard carbon design and provides valuable insights into the construction of high-rate anode for advanced sodium-ion batteries.