Photo: University of Freiburg

Uni Freiburg: Redox flow bat­tery with a long ser­vice life

Redox flow bat­ter­ies, also known as liq­uid bat­ter­ies, store elec­tri­cal ener­gy in dis­solved chem­i­cal com­pounds. They are regard­ed as an alter­na­tive to lithi­um-ion bat­ter­ies, espe­cial­ly for sta­tion­ary ener­gy stor­age. A team led by Prof. Dr. Ingo Kross­ing from the Insti­tute of Inor­gan­ic and Ana­lyt­i­cal Chem­istry at the Uni­ver­si­ty of Freiburg has suc­ceed­ed in devel­op­ing a non-aque­ous all-man­ganese flow bat­tery (all-MFB) whose active com­po­nents use sus­tain­ably avail­able man­ganese and have a long life­time. The researchers present the results of their work in the cur­rent issue of Advanced Ener­gy Mate­ri­als .

Active mate­ri­als are the chem­i­cal sub­stances need­ed for ener­gy stor­age in bat­ter­ies. The Freiburg sci­en­tists have now replaced the ele­ment vana­di­um, which was pre­vi­ous­ly used as the active mate­r­i­al, with the read­i­ly avail­able man­ganese. Kross­ing and his team pur­sued a new approach to make the sus­tain­able man­ganese work in the bat­tery: cou­pling the depo­si­tion of ele­men­tal man­ganese with the oxi­da­tion of man­ganese in the +II oxi­da­tion state to man­ganese +III has not been used before to store ener­gy elec­tro­chem­i­cal­ly. The new­ly devel­oped bat­tery achieves an ener­gy den­si­ty that is about twice as high as that of the pre­vi­ous stan­dard redox flow bat­tery with vanadium.

“With the elec­trolytes pre­sent­ed in our pub­li­ca­tion, ener­gy den­si­ties of up to 74 Wh L-1 are pos­si­ble,” explains Kross­ing. “In the first exper­i­ment, this is already much bet­ter than the ener­gy den­si­ty of the vana­di­um redox flow bat­tery, which has been researched since 1978.” Although fur­ther opti­mi­sa­tion of the bat­tery is still nec­es­sary, says the Freiburg chemist, “this sys­tem describes a com­plete­ly new and promis­ing struc­ture for sus­tain­able sta­tion­ary ener­gy storage.”

Orig­i­nal publication:
Schmuck­er, M. et al., Kross­ing, I. (2021): Inves­ti­ga­tions Towards a Non-Aque­ous Hybrid Redox-Flow Bat­tery with a Man­ganese Based Anolyte and Catholyte. In: Advanced Ener­gy Mate­ri­als. DOI: 10.1002/aenm.202101261