Anode pre-lithiation-pre-sodiation method, pre-lithiated and pre-sodiated anode, and lithium secondary battery comprising same
A method for pre-lithiation and pre-sodiation of a negative electrode, including the steps of: preparing a negative electrode including a negative electrode current collector, and a negative electrode active material layer on at least one surface of the negative electrode current collector. Then, applying and drying a first composition containing a lithium metal powder, a polymer binder and a dispersion medium onto the negative electrode active material layer to form a lithium metal layer. Next, applying and drying a second composition containing a sodium metal powder, a polymer binder and a dispersion medium onto the lithium metal layer to form a sodium metal layer. Then, dipping the negative electrode having the lithium metal layer and the sodium metal layer in an electrolyte for pre-lithiation and pre-sodiation. A pre-lithiated and pre-sodiated negative electrode obtained by the method and a lithium secondary battery including the same are also disclosed.
1. A method for pre-lithiation and pre-sodiation of a negative electrode, comprising:
preparing a negative electrode comprising a negative electrode current collector, and a negative electrode active material layer on at least one surface of the negative electrode current collector;
applying and drying a first composition comprising a lithium metal powder, a polymer binder and a dispersion medium onto the negative electrode active material layer to form a lithium metal layer;
applying and drying a second composition comprising a sodium metal powder, a polymer binder and a dispersion medium onto the lithium metal layer to form a sodium metal layer; and
dipping the negative electrode having the lithium metal layer and the sodium metal layer in an electrolyte for pre-lithiation and pre-sodiation.
2. The method for pre-lithiation and pre-sodiation of the negative electrode according to claim 1 , wherein the electrolyte for pre-lithiation and pre-sodiation comprises a lithium salt, a sodium salt and a non-aqueous solvent.
3. The method for pre-lithiation and pre-sodiation of the negative electrode according to claim 2 , wherein the lithium salt comprises at least one of LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi, lithium chloroborate, lithium lower aliphatic carboxylate, or lithium tetraphenylborate.
4. The method for pre-lithiation and pre-sodiation of the negative electrode according to claim 2 , wherein the sodium salt comprises at least one of NaCl, NaBr, NaI, NaClO 4, NaBF 4, NaB 10 Cl 10, NaPF 6, NaCF 3 SO 3, NaCF 3 CO 2, NaAsF 6, NaSbF 6, NaAlCl 4, CH 3 SO 3 Na, CF 3 SO 3 Na, (CF 3 SO 2 ) 2 NNa, sodium chloroborate, sodium lower aliphatic carboxylate, or sodium tetraphenylborate.
5. The method for pre-lithiation and pre-sodiation of the negative electrode according to claim 1 , wherein the lithium metal powder is loaded in an amount of 0.01 mg/cm 2 to 0.70 mg/cm 2 on the negative electrode active material layer.
6. The method for pre-lithiation and pre-sodiation of the negative electrode according to claim 1 , wherein the sodium metal powder is loaded in an amount of 0.05 mg/cm 2 to 2.0 mg/cm 2 on the lithium metal layer.
7. The method for pre-lithiation and pre-sodiation of the negative electrode according to claim 1 , wherein the lithium metal powder is loaded in an amount of 0.07 mg/cm 2 to 0.20 mg/cm 2 on the negative electrode active material layer.
8. The method for pre-lithiation and pre-sodiation of the negative electrode according to claim 1 , wherein sodium metal powder is loaded in an amount of 0.22 mg/cm 2 to 0.65 mg/cm 2 on the lithium metal layer.
9. A pre-lithiated and pre-sodiated negative electrode obtained by the method as defined in claim 1 .