ϵ-VOPO
A lithium battery with a cathode fabricated using an improved method for slurry formulation and electrode production. The cathode comprises the epsilon polymorph of vanadyl phosphate, ε-VOPO 4 , made from solvothermally synthesized H 2 VOPO 4 , and optimized to reversibly intercalate two Li-ions to reach full theoretical capacity with a coulombic efficiency of 98%. This material adopts a stable 3D tunnel structure and can extract two Li-ions per vanadium ion, giving a theoretical capacity of 305 mAh/g, with an upper charge/discharge plateau at around 4.0 V, and one lower at around 2.5 V. The ε-VOPO4 particles may be modified with niobium (Nb) to improve the cycling stability.
1 . A cathode for A lithium battery, comprising:
ε-VOPO 4 particles having a dual lithium ion exchange characteristic;
wherein the ε-VOPO 4 particles are solvothermally generated and modified to include β-VOPO 4 ; and
wherein the cathode has a capacity of at least 260 mAh/g at a discharge rate of C/20.
2 . The cathode of claim 1 , wherein the cathode has a capacity of at least 275 mAh/g at a discharge rate of C/20.
3 . The cathode of claim 1 , wherein the cathode has a capacity of at least 285 mAh/g at a discharge rate of C/20.
4 . The cathode of claim 1 , wherein the modified ε-VOPO 4 particles are modified with niobium.
5 . The cathode of claim 4 , wherein the cathode niobium concentration exceeds 1.0 mol %.
6 . The cathode of claim 4 , wherein the cathode niobium concentration exceeds 3.6 mol %.
7 . The cathode of claim 4 , wherein the cathode niobium concentration exceeds 6.0 mol %.
8 . A lithium battery, comprising:
a cathode formed with modified ε-VOPO 4 particles comprising β-VOPO 4 , having a dual lithium ion exchange characteristic,
wherein the modified ε-VOPO 4 particles are solvothermally generated, and wherein the cathode has a capacity of at least 260 mAh/g at a discharge rate of C/20; and
an anode.
9 . The lithium battery of claim 8 , wherein the cathode has a capacity of at least 275 mAh/g at a discharge rate of C/20.
10 . The lithium battery of claim 8 , wherein the cathode has a capacity of at least 285 mAh/g at a discharge rate of C/20.
11 . The lithium battery of claim 8 , wherein the solvothermally generated ε-VOPO 4 particles are modified with niobium.
12 . The lithium battery of claim 11 , wherein the cathode niobium concentration exceeds 1.0 mol %.
13 . The lithium battery of claim 11 , wherein the cathode niobium concentration exceeds 3.0 mol %.
14 . The lithium battery of claim 11 , wherein the cathode niobium concentration exceeds 6.0 mol %.
15 . The lithium battery of claim 8 , wherein the anode is a lithium metal anode.
16 . A lithium metal battery, comprising:
a cathode formed with ε-VOPO 4 particles having a dual lithium ion exchange characteristic, modified to include β-VOPO 4 ,
wherein the ε-VOPO 4 particles are solvothermally generated, and wherein the cathode has a capacity of at least 260 mAh/g at a discharge rate of C/10; and
a lithium metal anode.
17 . The lithium metal battery of claim 16 , wherein the ε-VOPO 4 particles are modified with niobium.
18 . The lithium metal battery of claim 17 , wherein the cathode niobium concentration exceeds 1.0 mol %.
19 . The lithium metal battery of claim 17 , wherein the cathode niobium concentration exceeds 3.6 mol %.
20 . The lithium metal battery of claim 17 , wherein the cathode niobium concentration exceeds 6.0 mol %.