A Japanese research group, having members among the Advanced Industrial Science and Technology (AIST) developed a new oxide negative-electrode and a new synthesis method to fabricate it, at lower temperatures, of about 200 to 300 degrees Celsius.
The electrode that AIST developed is a compound of titanium oxide (H2Ti12O25), and increases the energy density some 30% more, compared to lithium titanate. The charge-discharge capacity was also improved, the new electrode featuring a 225 mAh/g, unlike the lithium titanate, that has 175 mAh/g.
The researchers used sodium titanate (Na2Ti3O7) as their base material, and applied an acid treatment to it at a temperature of 60 degrees Celsius. The resulted substance, H2Ti3O7, has been treated at a higher temperature of 200 to 300 °C, obtaining the final H2Ti12O25.
The method they developed for synthesizing the titanium oxide is called “Soft Chemistry Synthesis”, and keeps the backbone architecture of the initial material, while changing its chemical composition.
Since it does not contain lithium, the titanium oxide solution is much cheaper. Moreover, the battery didn’t show signs of degradation after 50 charge-discharge cycles, having the same energy density it had after only 10 cycles.