Method for electrochemical pretreatment of vanadium positive electrode for lithium secondary batteries and vanadium positive electrode for lithium secondary batteries pretreated thereby

Patent metadata

Field	Value
Publication number	US-11646402-B2
Application number	US-201916769154-A
Country	US
Kind code	B2
Filing date	Jun 25, 2019
Priority date	Jul 18, 2018
Publication date	May 9, 2023
Grant date	May 9, 2023

Abstract

An electrochemical pretreatment method of a vanadium positive electrode for a lithium secondary battery, which can improve the lifetime characteristics of the positive electrode and the battery by inhibiting the leaching of vanadium when charging and discharging the lithium secondary battery using, for instance, vanadium oxide (V2O5) as a positive electrode, and a vanadium positive electrode for a lithium secondary battery pretreated thereby. The electrochemical pretreatment method of the vanadium positive electrode for a lithium secondary battery includes a) a step of discharging the lithium free vanadium positive electrode at a voltage of 1.9 V or more; b) an electrochemical pretreatment step of maintaining the discharged vanadium positive electrode of a) at an onset potential value or a potential value having a maximum current through a potentiostat; and c) a step of charging and discharging the pretreated vanadium positive electrode of b) at a voltage range of 2.1V to 4.0V.

First claim

The invention claimed is:

1. An electrochemical pretreatment method of a vanadium positive electrode for a lithium secondary battery, comprising:
a) a step of discharging a lithium-free vanadium positive electrode at a voltage of 1.9 V or more to obtain a discharged vanadium positive electrode;
b) an electrochemical pretreatment step of maintaining the discharged vanadium positive electrode of a) at an onset potential value through a potentiostat, or a potential value having a maximum current through a potentiostat to obtain a pretreated vanadium positive electrode; and
c) a step of charging and discharging the pretreated vanadium positive electrode of b) at a voltage range of 2.1 V to 4.0 V to obtain the vanadium positive electrode for the lithium secondary battery,
wherein the onset potential value and the potential value having the maximum current are derived by confirming a reduction peak of the lithium secondary battery using vanadium oxide as a positive electrode through a cyclic voltammetry, and
wherein the electrochemical pretreatment step is performed for 5 seconds to 60 seconds, and
wherein the surface of the vanadium positive electrode for the lithium secondary battery is in an omega (ω) phase and the inside of the vanadium positive electrode for the lithium secondary battery is in any one selected from the group consisting of alpha (α) phase, epsilon (ε) phase, delta (δ) phase, and gamma (γ) phase.

2. The electrochemical pretreatment method of the vanadium positive electrode for the lithium secondary battery according to claim 1 , wherein the reduction peak is confirmed by performing a cyclic voltammetry at a voltage of 1.0 V to 4.0 V and a scan rate of 1 mV/s to 10 mV/s.

3. The electrochemical pretreatment method of the vanadium positive electrode for the lithium secondary battery according to claim 1 , wherein the vanadium oxide is represented by the following Formula 1:
V a O b ,  [Formula 1]

wherein 1≤a≤6 and 2≤b≤13.

4. The electrochemical pretreatment method of the vanadium positive electrode for the lithium secondary battery according to claim 1 , wherein the vanadium oxide is vanadium pentoxide (V 2 O 5 ).

5. A vanadium positive electrode for a lithium secondary battery, obtained with the electrochemical pretreatment method of claim 1 , which has a surface of a stable irreversible state and an inside of a reversible state.

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Chang Wansoo
• Chae Jonghyun
• Kim Suhwan
• Lim Sung Chul

Classifications

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M4/1391 Primary

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/483

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title

• H01M4/0459 Primary

  Electrochemical doping, intercalation, occlusion or alloying · CPC title