Post-mortem electrolyte analysis
Post-mortem electrolyte analysis is a powerful diagnostic tool that provides insight into what actually happens inside a battery cell when its service life has expired or its performance has declined. By examining the electrolyte, we gain important insights into the condition, efficiency, and longevity of the battery cell.
Since the electrolyte directly influences everything from performance to failure, understanding its condition after use opens up the potential to improve design, increase safety, and extend battery life.
Significance in battery development and manufacturing
-
Understanding the role of electrolytes in battery health
Electrolytes are essential to the operation and longevity of battery cells, as they enable ion transport between electrodes. They also play a critical role in the formation of interphases such as the solid electrolyte interphase (SEI) on the anode and the cathode electrolyte interphase (CEI) on the cathode.
Importantly, cross-talk between the electrodes occurs through the electrolyte, making it a central medium in electrochemical interactions. The properties of the electrolyte directly impact various key aspects of battery performance including ionic conductivity, electrochemical stability, intrinsic safety, and aging behavior.
Notably, the electrolyte is the only component within a battery cell that is in contact with every other component. As such, its chemical stability is vital to overall cell health. Electrolyte degradation often leads to additional failure modes, emphasizing the importance of monitoring and understanding its behavior. Studying electrolytes in their post-use (post-mortem) state provides valuable insights into performance limitations and potential failure mechanisms. -
Accurate diagnosis drives design improvement
A detailed post-mortem analysis of used electrolytes reveals chemical changes, contamination, or material losses that may not be apparent through electrode analysis alone. By identifying the degradation mechanisms of the electrolyte, researchers can trace failure pathways, evaluate risks of thermal or electrochemical instability, and assess potential safety concerns.
These insights can directly inform the redesign and optimization of electrolyte formulations, ultimately contributing to improved performance, safety, and longer battery life. -
Applicability across different battery cell chemistries
The value of post-mortem electrolyte analysis extends beyond lithium-ion battery cells. It is equally relevant for batteries using alternative chemistries such as sodium-ion, zinc-ion, magnesium-ion, and redox flow batteries, all of which employ liquid electrolytes that degrade through different mechanisms.
Furthermore, electrolytes from semi-solid state cells can also be analyzed and reverse-engineered. By studying the behavior of degraded electrolytes, researchers enhance their understanding of each chemistry and support efforts to optimize electrolyte formulations for specific systems.
Industry applications
Post-mortem electrolyte diagnostics power progress for different energy sectors
-
Electric vehicles (EVs)
For ensuring battery reliability, safety, and lifespan to improve vehicle performance and customer satisfaction.
-
Consumer electronics
For optimization of battery life and safety in smartphones, laptops, and wearables by identifying electrolyte degradation.
-
Renewable energy storage
For enhancing the durability and efficiency of grid-scale and residential energy storage systems through electrolyte insights.
-
Aerospace and defense
For maintaining strict safety and performance standards for batteries used in critical applications.
-
Battery manufacturing and R&D
For driving innovation by understanding failure modes and refining electrolyte formulations for next-generation batteries.
-
Niche markets
Improving key-performance indicators of each customer in any application through tailored electrolyte solutions.
The process to get post-mortem electrolyte insights
-
1. Safe battery tear-down and electrolyte handling
Our facility is equipped for safe and controlled battery tear-downs, ensuring every step is performed under strict safety protocols. Battery cells are opened under a protective atmosphere to prevent unwanted reactions and ensure operator safety. Guided by a standardized disassembly protocol, we carefully extract, transfer, and store electrolytes while maintaining full contamination control.
All cell components are thoroughly washed, and washing solutions are harvested for further analysis, ensuring no detail is overlooked. From precise handling to compliant waste disposal, we prioritize both safety and data integrity throughout the entire process. -
2. Analysis of cell degradation
We investigate degradation phenomena across a wide range of cell formats, including cylindrical cells (18650, 21700, 4680), pouch cells, prismatic cells (PHEV-1), and blade cells. Our comprehensive analysis combines advanced electrochemical testing with high-resolution spectro-analytical and physicochemical methods—delivered in collaboration with trusted measurement partners.
From AES, XPS, XRD, TOF-SIMS, Raman, and NMR spectroscopy to SEM, TEM, XCT, and ARC imaging, we uncover the intricate changes within harvested electrodes. Electrochemical performance is further evaluated using three-electrode and lab-scale cell setups, while dissolution studies via ICP-MS and ICP-OES provide deep insight into elemental composition and material degradation.
This integrated approach enables a detailed understanding of aging and failure mechanisms—empowering you to enhance battery design and extend product life.
-
3. Analytical techniques for post-mortem electrolyte characterization
Our advanced analytical toolkit is designed to deliver precise and comprehensive insights into electrolyte condition and composition. We determine water and free-acid content using titration methods, while ionic conductivity and viscosity measurements reveal key performance indicators.
Through ion chromatography (IC), we analyze trace elements and salt concentrations with high sensitivity. Elemental impurities and further salt quantification are performed using ICP-OES, ensuring detailed chemical profiling. Gas chromatography (GC-FID) allows us to assess the purity and overall composition of the electrolyte, while Hazen color and turbidity analysis provides additional quality metrics.
We also perform flash point determination for safety evaluation, as well as melting point and thermal behavior analysis using differential scanning calorimetry (DSC). Together, these methods form a robust foundation for electrolyte diagnostics—delivering the data you need to optimize performance, safety, and reliability. -
4. Interpretation of analytical data to diagnose electrolyte failures
We go beyond data collection—turning complex analytical results into actionable insights. By combining chemical, physical, and electrochemical data, we uncover the root causes of electrolyte degradation and identify critical failure indicators.
Our approach includes benchmarking against reference data from fresh electrolytes, enabling precise comparisons that highlight deviations and degradation pathways. We also detect cross-talk between the electrolyte and electrodes, revealing hidden interactions that impact cell performance.
To validate findings, we perform electrochemical characterization using cells filled with fresh electrolyte based on reverse-engineered formulations—closing the loop between analysis and practical application. This comprehensive interpretation enables smarter design decisions and more robust battery systems.
Strategies for unraveling and interpreting physicochemical characteristics of the electrolyte
-
- Understanding the excess of salt hydrolysis and HF formation of the electrolyte
-
- Investigating how temperature influences conductivity and viscosity
- Understanding how to interpret deviations in aged electrolyte samples
-
- Identification of exact composition and the common contaminants in fresh and degraded electrolytes
- Discovering how elemental contamination correlates with long-term electrolyte instability or battery failure
- Electrode-electrolyte cross-talk, corrosion or electrochemical dissolution of casing, catalytic effects…
-
- Detection of organic solvent breakdown (carbonates, sulphates, esters…)
- Diagnosing degradation products from thermal or electrochemical abuse
-
- Associating trace metals introduced during electrolyte production or cycling (from component dissolution)
- Understanding the connection between metallic impurities and parasitic reactions and electrode plating
-
- Monitoring physical changes due to formation of insoluble particles or degradation of cell components
-
- Evaluating flammability of the fresh and degraded electrolytes
- Identifying the differences in electrolyte volatility due to salt, solvent, additive losses
- Understanding thermal stability of the electrolyte mixtures
Strategies for identifying cell aging mechanisms and failure modes
-
- Visual identification of swelling, venting, or leakage as first indicators of thermal or gas generation events
- Safe disassembly under inert atmosphere to prevent further reactions with air and moisture
- Careful harvesting of electrodes, separator, and residual electrolyte while maintaining orientation and avoiding cross-contamination
- Photo documentation to assist with correlating physical damage to failure symptoms
-
- Unravelling of the electrolyte formulation (i.e. salts, solvent blend, additives) to understand the designed functionality
- Identifying presence of additives through NMR or GC-MS to distinguish degradation products from intended components
-
- Identification of organic and inorganic decomposition products (oligomers, esters) from the breakdown of solvents
- Diagnosis of salt decomposition byproducts (i.e. PF5, HF) as indicators of hydrolysis
- Trace metal detection to indicate current collector corrosion or casing degradation
- Correlating decomposition profiles with cell history
(i.e., float tests or cycling at high C-rates)
-
- Identifying and quantification of gaseous byproducts (CO2, CO, H2, CH4, C2H4) from thermal runaway or overcharging
- Attribution of signature and dominant gas species to known electrolyte breakdown pathways (i.e. FEC decomposition results into formation of volatile fluorinated organic compounds such as fluoroacetaldehyde in combination with H2 and CO2 )
-
- Preliminary optical inspection for identification of cracking of electrode coating or any plating on electrode surfaces as well as integrity of the separator
- Electron microscopy and X-ray computed tomography for understanding dendrite formation or mechanical degradation of the electrode particles
- Detection of internal particle fracturing of void formation via XCT
- FIB-SEM EDX cross-sectional analysis for understanding metal deposition layer (i.e. Li plating, Cu migration) or any interfacial layer formation
-
- Detection of electrolyte decomposition products at electrode-electrolyte interphase by surface-sensitive techniques
- Elemental mapping of transition metal dissolution and possible deposition on negative electrodes
-
- Identifying chemical composition of SEI/CEI to identify organic/inorganic species (LiF, Li2CO3, ROCO2Li) and their change of bonding states over cycling
- Detecting additive decomposition or deposition of surface films
- Detection of graphitic vs amorphous carbon shifts via Raman for aged anodes
-
- Reconstructing half-cells to localize degradation to positive or negative electrode
- Comparison of capacity fade, impedance rise, or voltage hysteresis
- Impedance spectroscopy (EIS) or galvanostatic titration (GITT) to understand lithium diffusion or interfacial resistance information
-
- Evaluation of thermal stability and safety performance of harvested aged electrodes or residual electrolyte
Our State-of-the Art Infrastructure
From initial consultation to final results, our in-house analytical laboratory provides end-to-end support for your post-mortem electrolyte analysis needs. Equipped with cutting-edge technology and backed by expert know-how, we deliver fast, reliable, and high-quality data that drives your project forward.
