ICP-MS Analysis of Elemental Composition of Battery Raw Materials

Abstract

An inductively coupled plasma mass spectrometry (ICP‑MS) approach for multi‑element characterization of lithium‑ion battery cathode materials is presented. NMC811, NMC622, NMC532, and LFP were analyzed as representative examples. TraceCERT^® single and multielement certified reference materials were used for calibration, ensuring traceability and reliability across a 32-isotope analyte panel. The resulting method showed good linearity (R² <0.99) and high sensitivity (low/sub-ppb), enabling reliable composition verification and impurity screening.

Section Overview

• Introduction
• Experimental
• Results
• Conclusion
• Related Products

Introduction

The demand for high‑performance battery materials is rapidly increasing, driven by advances in electric vehicles and renewable energy storage. Among these materials, cathodes (Figure 1) play a pivotal role in determining overall efficiency and capacity.^1-3 Accurate determination of elemental composition in cathode active materials is essential for ensuring consistent electrochemical performance, verifying raw‑material quality, and supporting research and development in advanced battery technologies.^4,5

This study focuses on four representative lithium‑ion battery cathode materials - lithium nickel manganese cobalt oxide (NMC811, NMC532, NMC111)^6-8 and lithium iron phosphate (LFP).^9,10 Although their chemistries differ, they share similar analytical requirements, including quantification of major transition metals alongside trace‑level impurities, with sufficient breadth and sensitivity to support both developmental work and routine quality control. The workflow described here targets 32 elements to address these needs.

Inductively coupled plasma-mass spectrometry (ICP‑MS) offers broad elemental coverage together with the sensitivity required for both formulation optimization and contamination control.^11,12 In the present work, ICP-MS was combined with a standardized microwave‑assisted digestion procedure and controlled dilution protocol to provide reproducible quantification across a wide concentration range while maintaining matrix robustness suitable for battery materials.

High‑purity single‑ and multi‑element certified reference materials (CRMs), such as TraceCERT^® solutions, enable reliable and traceable multi‑point calibrations across major transition metals such as Ni, Co, Mn, and Fe, as well as alkali and alkaline‑earth elements including Li, Na, K, Mg, and Ca, together with other potential impurities. The use of multi‑component mixes simplifies standard preparation and handling without compromising accuracy, facilitating implementation in both quality‑control laboratories and research environments.

Overall, this application note outlines a robust and scalable ICP‑MS approach for elemental characterization of key lithium‑ion cathode materials. The method supports rapid screening of incoming raw materials, process intermediates, and post‑cycling powders while promoting consistent product quality and enabling continued innovation.

Experimental

Elemental analysis of the cathode active materials NMC811, NMC532, NMC111, and LFP was performed using an ICP‑MS workflow optimized for high‑matrix inorganic battery materials. All measurements were carried out on a ThermoScientific iCAP MSX instrument equipped with kinetic energy discrimination in helium mode to minimize polyatomic interferences commonly observed in transition‑metal‑rich matrices. A total of 32 isotopes were monitored with a dwell time of 0.1 s at normal resolution, with ten sweeps per measurement.

Calibration Standards Preparation

Calibration was performed using certified reference material (CRM) standards prepared at six levels (STD1 to STD6). A single mixed top calibration solution (STD1) was prepared by combining four CRM stock standards: a 10 mg/L multi-element mix with 17 elements (41135), a multi-element mix containing most elements at 10 mg/L (Ag, Al, Ba, Be, Bi, Cd, Co, Cr, Cu, Li, Mg, Mn, Ni, Pb, Sr, V, Zn) and Ca, Fe, K, and Na at 100 mg/L (54704), and single-element standards for As and B (01969 and 01932 ; 1000 mg/L each). Due to the non-uniform concentrations in the multi-element mix, different target concentrations were established in STD1: 5000 µg/L for Ca, Fe, K, and Na; 400 µg/L for As and B; and 500 µg/L for all other analytes. STD2–STD6 were prepared by serial dilution of STD1 to obtain concentrations of 250, 100, 50, 25, and 10 µg/L for the analytes targeted at 500 µg/L in STD1. Internal standards were not applied in this application note.

Sample Preparation

Approximately 15 mg of each cathode powder (NMC811, NMC532, NMC111, or LFP) was weighed into microwave digestion vessels. A mixed acid system of high purity nitric acid and hydrochloric acid in a 9:1 ratio was used, with a final digestion volume of 6 mL. Microwave digestion was conducted using a CEM Blade system under temperature-controlled conditions. The temperature was ramped from 25 °C to 210 °C over 15 min, followed by a hold of 20 min, with a maximum pressure limit of 500 psi. The applied microwave power was automatically adjusted by the instrument to achieve and maintain the programmed temperature profile.

Following digestion, the solutions were brought to 50 mL and subsequently diluted 1:1000 with high‑purity deionized water prior to ICP‑MS analysis. A 2% nitric acid rinse solution was used between measurements.

ICP-MS Operating Conditions

ICP-MS was operated in KED mode using helium as the collision gas. The method targeted the following 32 masses: ⁷Li, ⁹Be, ¹¹B, ²³Na, ²⁴Mg, ²⁷Al, ³⁹K, ⁴⁴Ca, ⁴⁸Ti, ⁵¹V, ⁵²Cr, ⁵⁵Mn, ⁵⁷Fe, ⁵⁹Co, ⁶⁰Ni, ⁶³Cu, ⁶⁶Zn, ⁷⁵As, ⁸⁸Sr, ⁹⁰Zr, ⁹⁵Mo, ¹⁰⁵Pd, ¹⁰⁷Ag, ¹¹¹Cd, ¹¹⁸Sn, ¹²¹Sb, ¹³⁷Ba, ¹⁸²W, ¹⁹³Ir, ¹⁹⁵Pt, ²⁰⁸Pb, ²⁰⁹Bi. Gas flows and handling parameters are summarized in Table 1. The humidifier was enabled to stabilize aerosol transport.

The analytical sequence included a procedural blank and wash step to verify carryover and baseline stability. Measurements were performed in triplicate for both calibration standards and samples.

Calibration and Sensitivity

The linearity coefficients (R²) and limits of detection (LOD) values determined for the method are listed in Table 2, allowing users to evaluate both the reliability of quantification and the practical detection limits relevant to their material analysis.

Results

This study describes the analysis of 32 elements by ICP-MS across four lithium-ion battery cathode active materials: NMC811, NMC532, NMC111, and LFP. The method monitored the specified isotope panel under Kinetic Energy Discrimination (KED) conditions with a dwell time of 0.1 s. Multi-point calibrations (six levels) prepared from single- and multi-element standard solutions delivered excellent linearity for key analytes. Representative coefficients of determination (R²) were at or above 0.99, with corresponding sub-ppb to low-ppb limits of detection for many targets. All calibration standards and sample solutions were measured in triplicate (n=3), and the relative standard deviation (RSD) values reported here were calculated accordingly. Procedural blanks were near zero across the analyte panel, confirming clean sample preparation and minimal carryover.

The NMC cathode materials were prepared in three compositions appropriate for high‑capacity battery research. ICP‑MS data corroborated that the synthesis was consistent with the intended stoichiometries. The relative proportions of Ni, Mn, and Co differentiated NMC811, NMC532, and NMC111 as expected. In contrast, LFP - an economically attractive and operationally stable cathode material - showed Fe as the predominant transition metal with negligible Ni, Mn, and Co content under the applied dilution (Table 3). 

The results indicate distinct compositional profiles among the investigated NMC variants, with variations in transition metal content that can significantly influence battery performance. The NMC811 material showed a higher Ni content with a measured molar ratio contribution of 0.83 compared to the nominal value of 0.8. The LFP material demonstrated a significantly higher Fe concentration relative to Li.

Across all four cathode material preparations/products, the comprehensive 32‑element scan indicated impurity levels at or below method detection limits (or near‑blank), supporting their suitability as high‑purity research materials.

Overall, the method provides a reliable approach for elemental characterization, supporting both quality control and research activities in battery technology.

Conclusion

This application note demonstrates a concise ICP‑MS workflow for multi‑element characterization of lithium‑ion battery cathode materials using TraceCERT^® single‑ and multi‑element certified reference materials (CRMs). Multi‑point calibrations delivered strong linearity (typical R² ≥ 0.99) and sub‑ppb to low‑ppb detection limits across many analytes, while accuracy and precision were verified over multiple standard levels with low %RSDs and recoveries close to nominal values.

Elemental results differentiated the intended stoichiometries among the NMC811, NMC622, and NMC532 materials based on the relative proportions of Ni, Co, and Mn, and confirmed the Fe‑dominant composition of LFP under the applied dilution scheme. The data also shows that the NMC811 is Ni‑enriched showing a higher Ni:Mn:Co ratio than the nominal composition, which is consistent with its design to enhance capacity. Across the full 32‑element panel, impurity levels were at or below method detection limits (data not shown), supporting the suitability of the analyzed materials as high‑purity research samples within the measured scope.

Taken together, the results show that certified reference materials used in conjunction with high purity acids provide a robust and traceable calibration framework for reproducible ICP‑MS analysis of battery cathode powders. This approach enables confirmation of stoichiometry, accurate quantification of nickel content, and sensitive impurity screening.