Speciation of Transition Metal Dissolution in Electrolyte from Common Cathode Materials
Leah Rynearson1, Cali Antolini1, Chamithri Jayawardana1
1Department of Chemistry, University of Rhode Island, Kingston, RI-02881, USA.
Angewandte Chemie (International Ed. in English)
|December 11, 2023
Summary
Transition metal dissolution causes capacity loss in lithium-ion batteries. This study reveals that the oxidation states of dissolved manganese and nickel depend on the cathode material, not the cycling potential.
Area of Science:
- Materials Science
- Electrochemistry
- Battery Technology
Background:
- Capacity fade in lithium-ion batteries is linked to transition metal dissolution from cathodes.
- Transition metal ions migrate through electrolytes and deposit on anodes, impacting battery performance.
- Limited research exists on the oxidation states of dissolved transition metals in electrolytes.
Purpose of the Study:
- To investigate the oxidation states of manganese (Mn) and nickel (Ni) ions dissolved in electrolytes.
- To correlate transition metal oxidation states with different cathode active materials and cycling potentials.
- To quantify deposited transition metal ions on anodes.
Main Methods:
- Electrolytes were extracted from cycled lithium-ion cells with four cathode materials: LiMn2O4 (LMO), LiNi0.5Mn1.5O4 (LNMO), LiNi0.8Mn0.1Co0.1O2 (NMC811), and LMRNMC.
- X-ray absorption spectroscopy (XAS) was used to determine the oxidation states of Mn and Ni in the electrolytes.
- Inductively coupled plasma-mass spectrometry (ICP-MS) quantified transition metal concentrations on anodes.
Main Results:
- Transition metal ions were detected in all electrolytes.
- The oxidation states of dissolved Mn and Ni were found to be dependent on the specific cathode material used.
- Cycling potential (high vs. standard) did not influence the oxidation states of Mn and Ni in the electrolyte.
Conclusions:
- The cathode material is the primary determinant of dissolved transition metal ion oxidation states in lithium-ion battery electrolytes.
- Understanding these oxidation states is crucial for mitigating capacity fade mechanisms.
- Further research can leverage this knowledge to design more stable cathode materials and electrolytes.
Keywords:
High Potential CathodesLithium-Ion BatteriesOxidation State SpeciationTransition Metal Ion DissolutionX-Ray Absorption SpectroscopyMore Related Videos
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