Scientists from Russia’s Skolkovo Institute of Science and Technology (Skoltech) have created a metal-ion cathode material based on titanium fluoride phosphate.
Researchers at Soltech’s Center for Energy Science and Technology (CEST) have reported their KTiPO4F cathode has exhibited a high electrochemical potential and “unprecedented” stability at high charge/discharge rates.
The researchers say their titanium-based positive electrode material, KTiPO4F, exhibited an electrode potential of 3.6 V in a potassium-ion cell.
The material endures 100 charge-discharge cycles at 5C with no capacity fading and the theoretica energy density is about 425 Wh/kg. However, Dr. Stanislav Fedorov’s (Assistant Professor at Skoltech Center for Energy Science and Technology) told BEST “the practical one is currently less, but can be improved”.
He added: “This cathode material is primarily intended for potassium-ion batteries. Though after some modifications it can be used in lithium- and sodium-ion batteries, but this is another story.
“Because they typically demonstrate low electrode potentials under 2.0V titanium-based materials have only been used as anode material in the past. This new material is not ideal of course, but its potential reaches a much higher value of 3.6V, which makes it attractive for cathode applications.”
They also reported that carbon-coated electrode materials displayed no capacity fading when cycled at 5C rate for 100 cycles.
Previously, the major stumbling block for using titanium compounds in cathode materials was the low electrochemical potential that limited the battery’s attainable specific energy.
The results of the study were published in Nature Communications.
Titanium is the tenth most common element in the Earth’s crust, and is mined all over the world.
Professor Stanislav Fedotov, said “This is an exceptional result that literally destroys the dominant paradigm long-present in the “battery community” stating that titanium-based materials can perform as anodes only, due to titanium’s low potential
“We believe that the discovery of the high-voltage KTiPO4F can give fresh impetus to the search and development of new titanium-containing cathode materials with unique electrochemical properties.”
Professor Artem Abakumov, director of CEST, said: “From the perspective of inorganic chemistry and solid state chemistry, this is an excellent example showing once again that rather than blindly following the generally accepted dogmas, we should look at things with eyes wide open.
“If you choose the right chemical composition, crystal structure and synthesis method, the impossible becomes possible and you can find new materials with unexpected properties and new opportunities for practical applications.”