Dataset for ball milling of sodium titanate anode materials

Sodium titanate is ball milled at different high energy speeds, showing a degradation of crystal structure but improvements in electrochemical properties in the resulting coin cells.Whislt lithium ion batteries are now the ubiquitous solution for portable energy storage, their wide-scale deployment will ultimately be limited by finite supplies of lithium. Alternative chemistries are therefore needed for long term deployment, although these might be in less mobile applications such as stationary grid storage, due to the inescapable increases in mass, making them less portable. Sodium ion batteries are one such solution, and whilst there are corollaries between Li and Na ion cathode chemistries, the anodes present more of a challenge. Sodium titantes are a family of materials which show paticular promise in this area, however no one phase currently satisfies the performance requirements in specific capacity and cycle stability. Here we show that the use of high energy ball milling can be used to access a low temeprature nanoscale phase of sodium titante, which shows particular promise for capacity and stability, along with superior rate capability, making it an interesting material for fast charging. The data here show X-ray diffraction, scanning electron microscopy, and a full set of characterisation of the battery performance metrics (cyclic voltammetry, galvanostatic charge and discharge, rate capability) for a series of sequentially milled samples with increasing milling speed, starting from the Na₂Ti₃O₇ phase. Initially this phase is presenved, but above a certain milling speed, we observe full breakdown of the crystal structure, followed by recrystallisation into thetrigonal Na₄Ti₅O₁₂ phase. This is accommpanied by a change in electrochemical profile, showing different processes for Na (de)insertion.