Green ball dianthus-like Na2Ti6O13 as high-rate performance anode for sodium-ion batteries

Benefitting from high abundance and low cost, sodium-ion batteries (NIBs) have been considered as promising energy storage device in large-scale application. However, low cycling stability and poor rate performance originated from the large size and heavy weight of the sodium ions hinder its application. In this work, a green ball dianthus-like sodium titanate (Na2Ti6O13) with a tunnel structure and large interlayer space has been synthesized via hydrothermal method and its formation mechanism has been investigated. As NIBs anode materials, Na2Ti6O13 exhibits excellent rate performance and superior cyclability. A high reversible capacity over 100 mA h g−1 is delivered at 1000 mA g−1 after 300 cycles. Even after 200 cycles at 500 mA g−1 and 200 cycles at 1000 mA g−1, the electrode can afford a capacity of 66 mA h g−1 at 2000 mA g−1 without apparent decay after 200 cycles. This outstanding performance can attribute to the unique nano-structure and large interlayer space of Na2Ti6O13 with a green ball dianthus-like morphology.