Photo-assisted fast charging of lithium manganese oxide spinel (LiMn
A process for charging a discharged electrochemical cell includes applying a voltage bias to the discharged electrochemical cell; and illuminating the cathode with a light source.
1. A method of generating Mn 4+ in an electrode of an electrochemical cell, the method comprising applying a charging current to the electrochemical cell, and simultaneously illuminating the electrode with visible light;
wherein the electrode comprises an active material comprising manganese; and
wherein applying the charging current to the electrochemical cell and simultaneously illuminating the electrode with visible light generates Mn 4+ in the electrode at a faster rate than the same electrochemical cell in the absence of illumination.
2. The method of claim 1 , wherein the electrode is a cathode.
3. The method of claim 2 , wherein the cathode comprises LiMn 0.5 Ni 0.5 O 2 , LiMn 1/3 Co 1/3 Ni 1/3 O 2 , LiMn 2 O 4 , LiFeO 2 , LiM 4 0.5 Mn 1.5 O 4 , or Li 1+x″ Ni α Mn β Co γ M 5 δ′ O 2−z″ F z″ ;
wherein:
M 4 is Al, Mg, Ti, B, Ga, Si, Mn, or Co;
M 5 is Mg, Zn, Al, Ga, B, Zr, or Ti;
0≤x″≤0.4; 0≤α≤1; 0≤β≤1; 0≤γ≤1; 0≤δ′≤1; and 0≤z″≤0.4;
with the proviso that at least one of α, β and γ is greater than 0.
4. The method of claim 2 , wherein the cathode comprises LiMn 0.5 Ni 0.5 O 2 , LiMn 1/3 Co 1/3 Ni 1/3 O 2 , LiMn 2 O 4 , LiCr 0.5 Mn 1.5 O 4 , LiCrMnO 4 , LiFe 0.5 Mn 1.5 O 4 , LiCoMnO 4 , LiNi 0.5 Mn 1.5 O 4 , LiMnPO 4 , or LizMnO 3 .
5. The method of claim 1 , wherein illuminating the electrode comprises illuminating the electrode with an externally powered light source.
6. The method of claim 5 , wherein the externally powered light source is a broadband white light source.
7. The method of claim 5 , wherein the externally powered light source is a monochromatic light source.
8. The method of claim 5 , wherein the externally powered light source is a light emitting diode, a xenon lamp, a laser, or optical fiber.
9. The method of claim 8 , wherein the externally powered light source is a light emitting diode.
10. The method of claim 1 , wherein the electrochemical cell is a lithium ion battery, a sodium ion battery, or a magnesium ion battery.
11. The method of claim 1 , wherein generating Mn 4+ in the electrode comprises oxidizing Mn 3+ to Mn 4+ in the electrode.
12. The method of claim 11 , further comprising, while generating Mn 4+ , ejecting a cation from the electrode.
13. The method of claim 11 , further comprising, while generating Mn 4+ , ejecting Li + from the electrode.
14. A method of generating Mn 4+ in an electrode of an electrochemical cell, the method comprising applying an external voltage bias to the electrochemical cell, and simultaneously illuminating the electrode with visible light;
wherein applying the external voltage bias to the electrochemical cell and simultaneously illuminating the electrode with visible light generates Mn 4+ in the electrode at a faster rate than the same electrochemical cell in the absence of illumination.