Electrode materials for magnesium batteries
A compound of formula A b′ Mg a M b X y or A b′ Mg a M b (XO z ) y for use as electrode material in a magnesium battery is disclosed, wherein A, M, X, b′, a, b, y, and z are defined herein.
1. A magnesium battery electrode comprising:
a current collector, and
an electroactive compound in electronic communication with the current collector, the electroactive compound having the formula of A b′ Mg a M b X y , and a layered structure,
wherein
A is one or more dopants selected from the group consisting of Al, Na, K, Zn, Ag, Cu, and mixtures thereof;
M is one or more transition metals selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, Ag, Zr, and mixtures thereof;
X is one or more anions selected from the group consisting of O, S, Se, F, and mixtures thereof;
0≦b′≦2.9;
0<a≦2.1;
0.5≦b≦2.9;
1.5≦y≦5.9; and
the layered structure comprises close-packed anion X lattice, layers of octahedrally-coordinated transition metal M, and layers of fully or partially occupied magnesium sites, wherein the layers of metal M and the layers of magnesium sites alternate;
provided that the compound is not layered Mg a VS 2 or layered Mg a ZrS 2 .
2. The magnesium battery electrode of claim 1 , wherein b′ is 0 and the electroactive compound has a formula of Mg a M b X y .
3. The magnesium battery electrode of claim 1 , wherein b is about 1 and y is about 2.
4. The magnesium battery electrode of claim 1 , wherein b is about 2 and y is about 4.
5. The magnesium battery electrode of claim 1 , wherein M is one or more transitional metals selected from the group consisting of Cr, Mn, Ni, Co, and mixtures thereof; and X is one or more anions selected from the group consisting of O, S, F, and mixtures thereof.
6. The magnesium battery electrode of claim 1 , wherein the electroactive compound has a unit cell atomic arrangement isostructural with a layered material comprising primarily Mg layer dispersed between primarily transition metal layers.
7. The magnesium battery electrode of claim 1 , wherein the electroactive compound has a magnesium diffusion barrier of less than 0.8 eV.
8. The magnesium battery electrode of claim 1 , wherein 0.05 b′3.9.
9. The magnesium battery electrode of claim 1 , wherein the electrode comprises an electrode layer comprising the electroactive compound, said electrode layer disposed on the current collector.
10. The magnesium battery electrode of claim 9 , wherein the electrode layer further comprises an electronically conductive additive.
11. The magnesium battery electrode of claim 9 , wherein the electrode layer further comprises a binder.
12. An energy-storing device comprising a first magnesium battery electrode of claim 1 .
13. The energy-storing device of claim 12 , further comprising a second magnesium battery electrode selected from the group consisting of a magnesium battery electrode of claim 1 , and a magnesium battery electrode comprising a magnesium metal or alloy as the electroactive material.