Content overflows the browser. Try zooming out (Ctrl + −) to see the full page. PDF Download
User Benefits Application News Fig.1 Charging and temperature conditions in a module (conceptual image) Using the materials listed in Table 1, pouch cells were assembled and subjected to cycle testing under the conditions shown in Table 2. Figure 2 shows the appearance of the cells for Conditions #2 and #3 at the end of the cycle tests. In the pouch cell tested under Condition #3, swelling caused by gas generated inside the cell was observed. Cell prototyping and cycle testing When lithium-ion batteries are used in EVs or ESS applications, numerous cells are connected in series and parallel to form modules, and multiple modules are further connected to construct a pack. In such configurations—where many cells are connected in series—the state of charge of individual cells varies, as shown in Figure 1. Moreover, because the cells are densely packed to reduce volume, the ambient temperature experienced by each cell also varies. In this application, we conducted cycle tests under overcharged or high-temperature conditions, disassembled the degraded pouch cells, and analyzed both the electrolytes and the electrodes. Introduction ICP-AES enables accurate quantification of cathode material dissolved in electrolytes. GC-MS assesses degradation from components in electrolytes with unknown usage. EDXRF easily evaluates transition metals, phosphorus, fluorine, and other elements deposited on electrodes. Analysis of Electrolyte and Electrode in LIB Degraded by Overcharge and High Temperature Tomoyuki Hiroki 1 , Jiajie Du 1 , Shota Hayakawa 1 , Hirokazu Moriya 1 , Teruko Toyoda 2 1 Shimadzu Corporation, 2 Shimadzu Techno-Research, Inc. Table 1 Structure of the pouch cell Cathode : NCM523 / PVDF / Carbon black Anode : Graphite / SBC+CMC / Carbon black Electrolyte salt : LiPF6 (1mol/L) Electrolyte solvent : EC: EMC: DEC (1: 1: 1) Electrolyte additives : VC (1vol.%), FEC (1vol.%) Separator : PP Table 2 Conditions of the cycle test (0.2C, 100 cycles) and SOH * at end of test # Cutoff voltage(V) Ambient temperature (˚C) SOH at 100 cycles (%) 1 4.0 40 99.8 2 5.0 40 39.2 3 5.6 40 38.7 4 4.0 50 89.8 5 4.0 60 89.5 (*) SOH (State of Health) indicates battery degradation and is defined as (full-charge capacity / initial full-charge capacity) × 100 (%). Fig.2 Condition of the pouch cells after cycle testing (left: #2, right: #3) Electrolytes and electrodes were extracted from the batteries degraded through the cycle tests (hereafter referred to as “degraded cells”) and analyzed using the instruments shown in Figures 3–5. It is known that electrolytes in degraded cells contain transition metals (Ni, Co, Mn) dissolved from the cathode active material 1) . In addition, electrolyte solvents are known to generate characteristic degradation products as deterioration progresses 2) . By analyzing these degradation-related elements and compounds, the degradation state of the battery can be assessed. In this article, we propose a multifaceted evaluation of electrolytes using ICP-AES and GC-MS. On both the cathode and anode, insulating layers known as CEI/SEI form on the electrode surfaces. Under improper charging conditions, excessive formation of these layers can lead to capacity loss. Furthermore, the dissolved metals from the cathode deposit and precipitate on the anode. These deposits can cause internal short circuits, posing risks such as fire hazards. While such electrode conditions are typically evaluated by ICP-AES or XPS to examine elemental content or surface chemical states, this article introduces a simpler evaluation method using EDXRF. Analysis of electrolyte and electrode Fig.5 EDXRF (Model: EDX-8100) Fig.3 ICP-AES (Model: ICPE-9820) Fig.4 GC-MS (Model: GCMS-QP2050 + AOC TM -30i) ICP-AES, GC–MS, EDXRF
Application News Table 3 shows the ICP-AES analysis results of transition metals in electrolytes. Because the electrolyte samples were measured after dilution, Table 3 lists both the measured values of the diluted solutions and the corresponding concentrations in original electrolytes. The analytical conditions are described later in Table 7. Figure 6 compares the concentrations of Ni, Mn, and Co in electrolytes under different cutoff voltages (#1, #2, #3), while Figure 7 presents comparisons under different ambient temperatures (#1, #4, #5). For the cutoff voltage conditions, the detected amounts of transition metals increased as the conditions became more severe. In contrast, under the different ambient temperature conditions, the detected amounts were below 1 ppm in all cases. Electrolyte analysis results (ICP-AES) Element Ni Mn Co Wavelength (nm) 231.604 257.610 238.892 Instrument Quantitation Limit *1 (10σ) (mg/L) 0.004 0.0002 0.001 Measured value of diluted solutions (mg/L) #1 0.004 0.00024 N.D. *2 #2 1.18 0.0237 0.264 #3 0.913 0.197 0.215 #4 0.014 0.00191 0.0025 #5 0.004 0.00022 N.D. Concentration in electrolytes *3 (mg/kg) #1 0.30 0.016 N.D. #2 179 3.59 40.0 #3 380 82.1 89.6 #4 0.72 0.098 0.13 #5 0.25 0.015 N.D. Table 3 ICP-AES analysis results of transition metals in electrolytes *1 Instrument quantitation limit = 10 × σ (standard deviation of the blank solution) × calibration curve slope. *2 N.D.: below the quantitation limit. *3 Concentration in electrolytes = measured value of diluted solutions × dilution factor. Refer to Table 7 for dilution factors. Fig.6 Comparison of Ni, Mn, and Co concentrations in electrolytes (by cutoff voltage) Fig.7 Comparison of Ni, Mn, and Co concentrations in electrolytes (by ambient temperature) Table 4 lists electrolyte degradation products 2),3) . Figure 8 shows example chromatograms of EDMP and DEDOHC detected under Condition #3. The peak area values of Compounds A–I obtained in SIM mode are summarized in Table 5. The analysis conditions are described later in Table 8. Figures 9 and 10 compare the peak areas of each compound for different cutoff voltages and different ambient temperatures, respectively. For the cutoff voltage conditions, the detected amounts of all compounds increased markedly, and for the ambient temperature conditions, compounds G, H, and I also showed an increasing trend. Electrolyte analysis results (GC-MS) Symbol Compounds (abb.) Quantitative ion (m/z) Qualitative ion (m/z) A Dimethyl phosphorofluoridate (DMFP) 90 80 B Ethyl methyl phosphorofluoridate (EMPF) 115 127, 97 C Diethyl phosphorofluoridate (DEPF) 101 129, 113 D Ethyl dimethyl phosphate (EDMP) 127 110, 109 E Diethyl methyl phosphate (DEMP) 141 113, 95 F Triethyl phosphate (TEP) 155 127, 99 G Dimethyl-2,5-dioxahexane dicarboxylate (DMDOHC) 102 91, 59 H Ethylmethyl-2,5-dioxahexane dicarboxylate (EMDOHC) 116 91, 89 I Diethyl-2,5-dioxahexane dicarboxylate (DEDOHC) 103 90, 89 12.1 12.2 0.0 0.5 1.0 1.5 (x100,000) 109.00 110.00 127.00 14.1 14.2 0.0 1.0 2.0 3.0 4.0 5.0 (x100,000) 89.05 90.00 103.00 Fig.8 Chromatograms of compounds detected from Condition #3 by SIM- mode (right: EDMP, left: DEDOHC) Table 4 Electrolyte degradation products list identified by GC-MS Symbol #1 #2 #3 #4 #5 A - 21,221 125,609 - - B - 261,555 1,804,650 - - C - 371,846 4,745,557 - - D - 38,925 352,338 - - E - 6,784 249,905 - - F - 30,207 612,945 - - G - 17,494 26,039 331 592 H 2,351 231,407 363,546 3.209 7,179 I 5,168 364,041 503,875 6,885 14,370 Table 5 Peak area values for each compounds
Application News Table 6 shows the appearance of the extracted electrode surfaces. Representative samples (#1, #2, and #4) are shown here. Visually, the sample for different cutoff voltages (#2) exhibited greater changes than the sample for different ambient temperatures (#4). In addition, comparison of the cathode and anode in sample #2 indicated that the anode showed more pronounced changes. Elemental analysis of these electrode surfaces was performed using EDXRF. Because EDXRF allows direct analysis of solid samples, the extracted electrodes could be analyzed without any pretreatment. Electrode analysis results (EDXRF) Table 6 Appearance of electrodes after cycle testing Fig.13 Overlaid elemental profiles in the anode (by cutoff voltage) Fig.9 Comparisons of peak area values of compounds in electrolytes (by cutoff voltage) Fig.10 Comparisons of peak area values of compounds in electrolytes (by ambient temperature) # Cathode Anode 1 2 4 Figures 11–14 show the analysis results for the different cutoff voltage conditions. Analysis conditions are provided later in Table 9. Figure 11 presents overlaid EDXRF profiles of Ni, Mn, and Co in the cathode, and Figure 12 compares their elemental amounts, shown as ratios relative to sample #1. Figures 13 and 14 summarize the anode results. Because Ni, Mn, Co, and F were not detected in the anode of sample #1, their values are compared relative to the cathode of sample #1, while P is compared relative to the anode of sample #1. Figures 12 and 14 show that transition-metal quantities changed in line with the ICP-AES electrolyte analysis, indicating dissolution from the cathode and deposition in the anode. Fluorine decreased in the cathode and increased in the anode, whereas phosphorus increased in both electrodes. #1 #2 #3 Fig.11 Overlaid elemental profiles in the cathode (by cutoff voltage) Fig.12 Comparison of cathode elemental amounts (by cutoff voltage) (Ratios relative to the #1 cathode) #1 #2 #3 Fig.14 Comparison of anode elemental amounts (by cutoff voltage) (Ni/Mn/Co/F relative to the #1 cathode; P relative to the #1 anode) Figures 15 and 16 present the comparison of elemental amounts for the different ambient temperatures. As in Figures 12 and 14, the values are shown as ratios with each elemental amount in sample #1 set to 1. No changes in transition metals were observed in the cathode, and none were detected in the anode under any condition. In contrast, phosphorus showed an increasing trend with higher ambient temperature, although the change was smaller compared with samples #2 and #3. Fig.15 Comparison of cathode elemental amounts (by ambient temperature) (Ratios relative to the #1 cathode) Fig.16 Comparison of anode elemental amounts (by ambient temperature) (Ni/Mn/Co/F relative to the #1 cathode; P relative to the #1 anode)
Application News www.shimadzu.com/an/ Shimadzu Corporation © Shimadzu Corporation, 2026 For Research Use Only. Not for use in diagnostic procedures. This publication may contain references to products that are not available in your country. Please contact us to check the availability of these products in your country. The content of this publication shall not be reproduced, altered or sold for any commercial purpose without the written approval of Shimadzu. See https://www.shimadzu.com/about/trademarks/index.html for details. Third party trademarks and trade names may be used in this publication to refer to either the entities or their products/services, whether or not they are used with trademark symbol “TM” or “”. Shimadzu disclaims any proprietary interest in trademarks and trade names other than its own. The information contained herein is provided to you "as is" without warranty of any kind including without limitation warranties as to its accuracy or completeness. Shimadzu does not assume any responsibility or liability for any damage, whether direct or indirect, relating to the use of this publication. This publication is based upon the information available to Shimadzu on or before the date of publication, and subject to change without notice. First Edition: Jan. 2026 01-01064-EN AOC is a trademark of Shimadzu Corporation or its affiliated companies in Japan and/or other countries. [Configuration] Instrument : ICPE-9820 Nebulizer : Nebulizer, PFA1S Chamber : Cyclonic Chamber for Hydrofluoric Acid Extension Pipe : Made of Quartz Torch : Organic Solvent Torch Drain : Hydrofluoric Acid Resistant Drain Auto Sampler : AS-10 [Analysis Conditions] RF Power : 1.40 kW Plasma Gas Flowrate : 20.0 L/min Auxiliary Gas Flowrate : 0.70 L/min Carrier Gas Flowrate : 0.75 L/min View Direction : Axial [Sample Pretreatment] Dilution Solvent : Ethanol : Pure Water = 1 : 1 Dilution Factor* : #1 : 68.2 #2 : 151 #3 : 416 #4 : 51.5 #5 : 68.8 Internal Standard : Germanium (Ge) 10 ppm * The dilution factor varies depending on the amount of electrolytes collected. Table 7 ICP-AES Analytical Conditions <Related Applications> 1. Analysis of Elemental Impurities in Lithium-Ion Secondary Battery Electrolytes Using the ICPE-9800 Series, Application News No. 01-00702-en 2. GC/MS Analysis of Fluorophosphates as Decomposition Products in Lithium Battery Electrolyte, Application News No. 05 -SCA-280-105-EN Analysis of the electrolytes from degraded batteries using ICP-AES and GC-MS revealed dissolution of transition metals as well as the formation of degradation products. Furthermore, EDXRF analysis of the electrodes enabled straightforward detection of changes in elemental composition, including transition metals, fluorine, and phosphorus. These analytical techniques allow for a multifaceted evaluation of battery degradation. In real-world battery operation, fluctuations in charging conditions and ambient temperature introduce variability in degradation states. By assessing degradation mechanisms individually, as demonstrated in this report, it is possible to obtain insights that contribute not only to improving intrinsic battery performance but also to optimizing implementation methods and control conditions. Summary [Configuration] GC-MS Model : GCMS-QP2050 Autoinjector : AOC-30i [GC] Column : SH-I-5MS (P/N 221-75940-30) (30 m × 0.25 mm I.D., 0.25 μm) Inj. Temp. : 250 ˚C Inj. Mode : Split Split Ratio : 10 Carrier Gas : He, constant linear velocity (36 cm/s) Column Temp. : 40 ˚C (3 min) → 3 ˚C/min → 60 ˚C→ 30 ˚C/min → 210 ˚C (20 min) → 10 ˚C/min → 280 ˚C (5 min) [MS] Ion Source Temp. : 230 ˚C Interface Temp. : 280 ˚C Pumping speed : 255 L/s Acquisition Mode : SIM SIM monitoring m/z : Refer to Table 4 Table 8 GC-MS Analytical Conditions Instrument : EDX-8100 Elements : 6C-92U Analysis group : Qualitative / quantitative analysis Detector : SDD X-ray tube : Rh target Tube Voltage : 15 [kV] (C-S) (Cl-V), 50 [kV] (Cr-U) Tube current : Auto [μA] Collimator : 10 [mmφ] Primary filter : Non (C-S), #2 (Cl-V), #3 (Cr-U) Atmosphere : Vacuum Integral time : 60 [s] x 3 (C-S), (Cl-V), (Cr-U) Dead time : Max. 30 [%] Table 9 EDXRF Analytical Conditions <References> 1) Xuanting Wu, et al., “A functional slurry additive for robust interphase and stabilized high-voltage nickel-rich cathodes in lithium-ion batteries,” Chemical Engineering Journal, 509 (2025) 161446 2) Waldemar Weber, et al., “Ion and gas chromatography mass spectrometry investigations of organophosphates in lithium ion battery electrolytes by electrochemical aging at elevated cathode potentials,” Journal of Power Sources, 306 (2016) 193- 199 3) Martin Grützke, Waldemar Weber, Martin Winter and Sascha Nowak, “Structure determination of organic aging products in lithium-ion battery electrolytes with gas chromatography chemical ionization mass spectrometry (GC-CI-MS)”, RSC Adv., 6 (2016), 57253
Please fill out the survey Related Products Some products may be updated to newer models. ICPE-9800 Series Multitype ICP Emission Spectrometers EDX-8100 Energy Dispersive X-ray Fluorescence Spectrometer GCMS-QP2050 Gas Chromatograph Mass Spectrometer Related Solutions Clean Energy Lithium-ion Battery Electronics Electronic Component Automotive Price Inquiry Product Inquiry Technical Service / Support Inquiry Other Inquiry Powered by TCPDF (www.tcpdf.org)