Nickel Manganese Cobalt Research Articles

Enhancing Cycling Stability of Lithium Metal Batteries by a Bifunctional Fluorinated Ether

AbstractThe lifespan of lithium (Li) metal batteries (LMBs) can be greatly improved by the formation of inorganic‐rich electrode‐electrolyte interphases (EEIs) (including solid‐electrolyte interphase on anode and cathode‐electrolyte interphase on cathode). In this work, a localized high‐concentration electrolyte containing lithium bis(fluorosulfonyl)imide (LiFSI) salt, 1,2‐dimethoxyethane (DME) solvent and 1,2‐bis(1,1,2,2‐tetrafluoroethoxy)ethane (BTFEE) diluent is optimized. BTFEE is a fluorinated ether with weakly‐solvating ability for LiFSI so it also acts as a co‐solvent in this electrolyte. It can facilitate anion decomposition at electrode surfaces and promote the formation of more inorganic‐rich EEI layers. With an optimized molar ratio of LiFSI:DME:BTFEE = 1:1.15:3, LMBs with a high loading (4 mAh cm−2) lithium nickel manganese cobalt oxide (LiNi0.8 Mn0.1 Co0.1) cathode can retain 80% capacity in 470 cycles when cycled in a voltage range of 2.8–4.4 V. The fundamental understanding on the functionality of BTFEE revealed in this work provides new perspectives on the design of practical high‐energy density battery systems.

Application of collaborative perception computing in electrochemical impact analysis of nickel rich cathode material

As a high-performance lithium-ion battery cathode material, nickel rich cathode material (NRCM) has the characteristics of high capacity and long cycle life, which has attracted the attention of researchers. The electrochemical performance of NRCM is influenced by various factors. Traditional experimental methods require a lot of time and resources, and cannot fully reveal the complex interactions between these influencing factors. To address this issue, collaborative perception computing has been introduced into electrochemical analysis. In the electrochemical impact analysis of NRCM, multiple sensing nodes can be used to collect and share electrochemical performance data, and data processing and analysis can be carried out through collaborative sensing calculation methods. A comprehensive analysis of the effects of different factors on the performance of NRCM, as well as optimization of material structure and battery design, can greatly improve the efficiency of data collection. In this study, the electrochemical performance of NRCM would be analyzed using a collaborative perception based electrochemical analysis algorithm using collaborative perception computing. In the experiment, electrochemical analysis was conducted on the 523, 622, and 811 ratio schemes of LiNixCoyMn1-x-yO2 ternary cathode material LiNixCoyMn1-x-yO2. After experimental verification, the average discharge specific capacities of nickel cobalt manganese ternary cathode materials in the ratios of 523, 622, and 811 were 174.52MAh/g, 184.75MAh/g, and 200.73MAh/g, respectively. These results indicated that the 811 ratio of nickel cobalt manganese ternary cathode material exhibited the best performance in terms of discharge specific capacity, and had obvious advantages compared to the other two ratios. Collaborative perception computing has brought new research ideas and methods to the field of lithium-ion battery research, which has promoted further research and development of cathode material properties.

Temperature-dependent hysteresis model for Li-ion batteries

The increasing importance of accurate battery state estimations in advanced Battery Management Systems (BMS) underscores the need for precise modelling of battery behaviour and characteristics. While equivalent circuit models are widely utilized for their low computational demands, they face challenges in maintaining precision and adaptability during dynamic conditions, posing a persistent concern for future advancements. This study focuses specifically on the battery hysteresis effect, a complicating factor in the modelling and estimation processes. Open circuit voltage (OCV) measurements and parameter identification for equivalent circuit models were conducted on prevalent Li-ion battery technologies, namely nickel-manganese–cobalt (NMC) and lithium-iron-phosphate (LFP). The experimental results indicate the hysteresis effect becomes more significant with lower temperatures. In this paper, a battery model covering the temperature influence on the hysteresis effect is proposed. The proposed model exhibits an average root mean square error of less than 13 mV. The model holds promise for application in modern battery management systems, offering an enhancement to state-of-charge estimation methodologies.

Carbon sphere @ nickel cobalt manganese trinary metal oxide composite synthesized via optimal temperature water bath technique for hybrid supercapacitors

Carbon sphere @ nickel cobalt manganese trinary metal oxide composite synthesized via optimal temperature water bath technique for hybrid supercapacitors

Resynthesis of Ni-rich lithium nickel manganese cobalt oxide cathode materials from the industrial leachate of spent Li-ion batteries: The effect of PF6− species from electrolyte

A significant rise in the generation of spent Li-ion batteries (LIBs) is expected due to the widespread usage of LIBs in various applications. The benefit of spent LIB valorization can be maximized by a high value-added recycling process. The resynthesis of cathode active materials (CAMs), a promising recycling method that directly produces CAMs from LIB leachate, is explored in this study. We resynthesize Ni-rich LiNi0.9Co0.05Mn0.05O2 (NCM955) CAMs via coprecipitation and sintering by varying the amount of PF6−, which can raise environmental concerns, in industrial LIB leachate. Our first employment of glow discharge mass spectrometer in the investigation of PF6− decomposition behavior reveals that the small amounts of PO43− are precipitated into NCM precursors and F− remains in the leachate during resynthesis process. The incorporation of PF6− species during the coprecipitation results in an enlargement of crystal lattice parameters. The incorporated PF6− species increases the ratio of Ni2+ to Ni3+ and leads to the formation of LixPOyFz on the surface of NCM, which exerts a positive effect on the overall LIB performance. This study is the first attempt where the effect of PF6− species from LIB electrolyte is investigated in the resynthesis of the state-of-the-art NCM955 from industrial LIB leachate.

Analysis of the Ecological Footprint from the Extraction and Processing of Materials in the LCA Phase of Lithium-Ion Batteries

The development of batteries used in electric vehicles towards sustainable development poses challenges to designers and manufacturers. Although there has been research on the analysis of the environmental impact of batteries during their life cycle (LCA), there is still a lack of comparative analyses focusing on the first phase, i.e., the extraction and processing of materials. Therefore, the purpose of this research was to perform a detailed comparative analysis of popular electric vehicle batteries. The research method was based on the analysis of environmental burdens regarding the ecological footprint of the extraction and processing of materials in the life cycle of batteries for electric vehicles. Popular batteries were analyzed: lithium-ion (Li-Ion), lithium iron phosphate (LiFePO4), and three-component lithium nickel cobalt manganese (NCM). The ecological footprint criteria were carbon dioxide emissions, land use (including modernization and land development) and nuclear energy emissions. This research was based on data from the GREET model and data from the Ecoinvent database in the OpenLCA programme. The results of the analysis showed that considering the environmental loads for the ecological footprint, the most advantageous from the environmental point of view in the extraction and processing of materials turned out to be a lithium iron phosphate battery. At the same time, key environmental loads occurring in the first phase of the LCA of these batteries were identified, e.g., the production of electricity using hard coal, the production of quicklime, the enrichment of phosphate rocks (wet), the production of phosphoric acid, and the uranium mine operation process. To reduce these environmental burdens, improvement actions are proposed, resulting from a synthesized review of the literature. The results of the analysis may be useful in the design stages of new batteries for electric vehicles and may constitute the basis for undertaking pro-environmental improvement actions toward the sustainable development of batteries already present on the market.

Study on Discharge Characteristic Performance of New Energy Electric Vehicle Batteries in Teaching Experiments of Safety Simulation under Different Operating Conditions

High-voltage heat release from batteries can cause safety issues for electric vehicles. Relevant scientific research work is carried out in the laboratory. The battery safety of laboratory experiments should not be underestimated. In order to evaluate the safety performance of batteries in the laboratory testing of driving conditions of electric vehicles, this paper simulated and compared the discharge characteristics of two common batteries (lithium iron phosphate (LFP) battery and nickel–cobalt–manganese (NCM) ternary lithium battery) in three different operating conditions. The operating conditions are the NEDC (New European Driving Cycle), WLTP (World Light Vehicle Test Procedure) and CLTC-P (China light vehicle test cycle) for normal driving of electric vehicles. LFP batteries have a higher maximum voltage and lower minimum voltage under the same initial voltage conditions, with a maximum voltage difference variation of 11 V. The maximum current of WLTP is significantly higher than NEDC and CLTC-P operating conditions (>20 A). Low current discharge conditions should be emulated in teaching simulation and experiments for safety reasons. The simulation data showed that the LFP battery had good performance in maintaining the voltage plateau and discharge voltage stability, while the NCM battery had excellent energy density and long-term endurance.

Transfer learning from synthetic data for open-circuit voltage curve reconstruction and state of health estimation of lithium-ion batteries from partial charging segments

Data-driven models for battery state estimation require extensive experimental training data, which may not be available or suitable for specific tasks like open-circuit voltage (OCV) reconstruction and subsequent state of health (SOH) estimation. This study addresses this issue by developing a transfer-learning-based OCV reconstruction model using a temporal convolutional long short-term memory (TCN-LSTM) network trained on synthetic data from an automotive nickel cobalt aluminium oxide (NCA) cell generated through a mechanistic model approach. The data consists of voltage curves at constant temperature, C-rates between C/30 to 1C, and a SOH-range from 70% to 100%. The model is refined via Bayesian optimization and then applied to four use cases with reduced experimental nickel manganese cobalt oxide (NMC) cell training data for higher use cases. The TL models’ performances are compared with models trained solely on experimental data, focusing on different C-rates and voltage windows. The results demonstrate that the OCV reconstruction mean absolute error (MAE) within the average battery electric vehicle (BEV) home charging window (30% to 85% state of charge (SOC)) is less than 22mV for the first three use cases across all C-rates. The SOH estimated from the reconstructed OCV exhibits an mean absolute percentage error (MAPE) below 2.2% for these cases. The study further investigates the impact of the source domain on TL by incorporating two additional synthetic datasets, a lithium iron phosphate (LFP) cell and an entirely artificial, non-existing, cell, showing that solely the shifting and scaling of gradient changes in the charging curve suffice to transfer knowledge, even between different cell chemistries. A key limitation with respect to extrapolation capability is identified and evidenced in our fourth use case, where the absence of such comprehensive data hindered the TL process.

A Multilayer Doyle-Fuller-Newman Model to Optimise the Rate Performance of Bilayer Cathodes in Li Ion Batteries

Bilayer cathodes comprising two active materials are explored for their ability to improve lithium-ion battery charging performance. Electrodes are manufactured with various arrangements of lithium nickel manganese cobalt oxide Li[Ni0.6Co0.2Mn0.2]O2 (NMC622) and lithium iron phosphate LiFePO4 (LFP) active particles, including in two different discrete sub-layers. We present experimental data on the sensitivity of the electrode C rate performance to the electrode design. To understand the complex bilayer electrode performance, and to identify an optimal design for fast charging, we develop an extension to the Doyle-Fuller-Newman (DFN) model of electrode dynamics that accommodates different active materials in any number of sub-layers, termed the multilayer DFN (M-DFN) model. The M-DFN model is validated against experimental data and then used to explain the performance differences between the electrode arrangements. We show how the different open circuit potential functions of NMC and LFP can be exploited synergistically through electrode design. Manipulating the Li electrolyte concentration increases achievable capacity. Finally the M-DFN model is used to further optimize the best performing bilayer electrode arrangement by adjusting the ratio of the LFP and NMC sub-layer thickness.

Tổng hợp vật liệu LiNi0,9Mn0,05Co0,05O2 bằng phương pháp phản ứng pha rắn (NMC9.5.5-PR) ứng dụng chế tạo pin ion liti

Nickel-manganese-cobalt (NMC) transition metal oxide-based layered structural materials are evaluated a promising material for applications as cathode in lithium-ion batteries. In this study, we have successfully synthesized nickel-rich NMC material LiNi0.9Mn0.05Co0.05O2 by solid-state reaction method (NMC9.5.5- PR). The CR2032-type lithium-ion battery is also successfully fabricated from NMC material to serve the study of electrochemical properties. The NMC9.5.5-PR material exhibits outstanding discharge specific capacity when providing a maximum specific capacity of up to 212.4 mAh/g at a current density of 10 mA/g. However, the cycle efficiency survey results show that the NMC9.5.5-PR material has some disadvantages (only maintaining 81.6% of the discharge specific capacity after 50 continuous charge-discharge cycles at current density of 10 mA/g). These electrochemical properties indicate that it is necessary to further improve the cyclic efficiency of NMC9.5.5-PR material but preserving its outstanding electrical energy storage capacity. Successfully accomplishing this goal, we believe that NMC-9.5.5-PR or a material based on NMC9.5.5-PR will be one of the suitable materials to fabricate positive electrodes used in lithium-ion batteries.

Innovations and strategies for optimizing lithium-ion battery performance: From material advancements to system management

This paper explores the multifaceted advancements in lithium-ion battery (LIB) technology, focusing on material innovations and engineering strategies aimed at optimizing performance, safety, and efficiency. We delve into the development of advanced cathode materials like lithium nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP), highlighting their contributions to enhancing energy density and safety. The investigation extends to silicon-based anode materials, underscoring their potential to significantly increase energy storage capacity despite challenges related to volume expansion. Furthermore, we discuss electrolyte optimization techniques that promise to improve battery safety through the use of non-flammable ionic liquids and solid-state electrolytes. Engineering strategies, including microstructure design of electrodes and thermal management systems, are analyzed for their role in improving electrochemical performance and extending battery lifespan. Smart battery management systems (BMS) are also examined for their ability to optimize battery usage through real-time monitoring and predictive analytics. Through a comprehensive review and quantitative analysis, this study presents a cohesive overview of current trends and future directions in LIB technology.

Efficient Leaching of Metal Ions from Spent Li-Ion Battery Combined Electrode Coatings Using Hydroxy Acid Mixtures and Regeneration of Lithium Nickel Manganese Cobalt Oxide

Extensive use of Li-ion batteries in electric vehicles, electronics, and other energy storage applications has resulted in a need to recycle valuable metals Li, Mn, Ni, and Co in these devices. In this work, an aqueous mixture of glycolic and lactic acid is shown as an excellent leaching agent to recover these critical metals from spent Li-ion laptop batteries combined with cathode and anode coatings without adding hydrogen peroxide or other reducing agents. An aqueous acid mixture of 0.15 M in glycolic and 0.35 M in lactic acid showed the highest leaching efficiencies of 100, 100, 100, and 89% for Li, Ni, Mn, and Co, respectively, in an experiment at 120 °C for 6 h. Subsequently, the chelate solution was evaporated to give a mixed metal-hydroxy acid chelate gel. Pyrolysis of the dried chelate gel at 800 °C for 15 h could be used to burn off hydroxy acids, regenerating lithium nickel manganese cobalt oxide, and the novel method presented to avoid the precipitation of metals as hydroxide or carbonates. The Li, Ni, Mn, and Co ratio of regenerated lithium nickel manganese cobalt oxide is comparable to this metal ratio in pyrolyzed electrode coating and showed similar powder X-ray diffractograms, suggesting the suitability of α-hydroxy carboxylic acid mixtures as leaching agents and ligands in regeneration of mixed metal oxide via pyrolysis of the dried chelate gel.

A thermal management design using phase change material in embedded finned shells for lithium-ion batteries

Phase change material (PCM) has recently been regarded as a promising thermal management means for lithium-ion (Li-ion) batteries. However, solid-liquid phase change of many current PCMs occurs in a narrow temperature range, and the cooling performance of their liquid phase is rather poor. To tackle these issues, this article presents a battery thermal management (BTM) design which injects PCM into an aluminum shell around each cell, and machines the shell inner surfaces into a row of straight rectangular fins immersed into the PCM and its outer surfaces into a plain-fin shape exposed in the air. In the mild thermal conditions, the finned shells of two adjacent cells can be embedded and passive PCM cooling is employed. Once the PCM completely melts, the shells will move apart and an airflow will be driven through the gap between them. The BTM design can also protect Li-ion batteries in a freezing environment, by taking advantage of PCM solidification when the finned shells return to their embedded configuration. A series of experiments were conducted to examine its effectiveness on two 50Ah lithium nickel cobalt manganese oxide (NCM) prismatic batteries, which were discharged at a capacity-rate of 2C and at room temperatures of T0=25∘C, 40∘C and −10∘C. It is shown that in the battery discharge at T0=25∘C, PCM in the embedded finned shells effectively reduced the average battery-surface temperature (T¯) and the maximum temperature difference (ΔTmax) by 21% and 36.7%, respectively, compared to bare batteries. At T0=40∘C, this BTM design successfully limited the growth of T¯ to 9.0∘C and led to ΔTmax no more than 1.5∘C. As to the low-temperature scenario, it maintained the batteries at temperatures above T0 for 55.2% longer than those without any BTM protections. Its cooling performance was also compared with that of the conventional liquid-cooling scheme using a bottom serpentine-channel cooling plate. All these results clearly demonstrate that the BTM design in this article can compensate for the deficiencies of conventional PCM-based BTM schemes. Regardless of whether the PCM phase change is available, it has well coped with different thermal management demands of Li-ion batteries.

Stabilized Nickel‐Rich‐Layered Oxide Electrodes for High‐Performance Lithium‐Ion Batteries

Next‐generation Li‐ion batteries are expected to exhibit superior energy and power density, along with extended cycle life. Ni‐rich high‐capacity layered nickel manganese cobalt oxide electrode materials (NMC) hold promise in achieving these objectives, despite facing challenges such as capacity fade due to various degradation modes. Crack formation within NMC‐based cathode secondary particles, leading to parasitic reactions and the formation of inactive crystal structures, is a critical degradation mechanism. Mechanical and chemical degradation further deteriorate capacity and lifetime. To mitigate these issues, an artificial cathode electrolyte interphase can be applied to the active material before battery cycling. While atomic layer deposition (ALD) has been extensively explored for active material coatings, molecular layer deposition (MLD) offers a complementary approach. When combined with ALD, MLD enables the deposition of flexible hybrid coatings that can accommodate electrode material volume changes during battery operation. This study focuses on depositing ‐titanium terephthalate thin films on a electrode via ALD‐MLD. The electrochemical evaluation demonstrates favorable lithium‐ion kinetics and reduced electrolyte decomposition. Overall, the films deposited through ALD‐MLD exhibit promising features as flexible and protective coatings for high‐energy lithium‐ion battery electrodes, offering potential contributions to the enhancement of advanced battery technologies and supporting the growth of the EV and stationary battery industries.

Numerical and experimental analysis of battery thermal management of 21700 Nickel Manganese Cobalt lithium-ion battery

High discharge rates in 21700 NMC Lithium-Ion Batteries (LIBs) leads to elevated temperatures, negatively impacting battery performance and longevity. This study examines the integration of phase change materials to address this issue. Phase change materials absorb heat through sensible and latent heat mechanisms, effectively reducing battery temperature. At discharge rates of 0.5 C, 1 C, and 1.5 C, phase change materials decreased battery temperature by 4.12 %, 7.32 %, and 8.16 %, respectively, ensuring optimal operating conditions. Incorporating phase change materials within battery modules minimizes cell spacing, leading to a smaller battery pack size and reduced costs. This compact design is achieved by exploiting phase change materials ability to store and release large amounts of heat while maintaining a nearly constant temperature. Furthermore, analyzing temperature variations across diverse surfaces within battery modules provides valuable insights for cooling technology development. The integration of Phase Change Materials effectively regulates temperatures, particularly under high discharge rates, offering significant implications for battery performance and longevity. This study highlights the potential of phase change materials in improving LIBs thermal management, which is crucial for electric vehicle applications and other high-power-demand scenarios. By addressing temperature-related challenges, phase change materials integration contribute to the advancement of more efficient, reliable, and safer LIBs.

A comparative study on the production of Ni1/3Co1/3Mn1/3C2O4 cathode precursor material for lithium-ion batteries using batch and slug-flow reactors

The intermittent nature of the renewable energy sources drifts research interest towards various electrochemical energy storage devices, such as the lithium ion battery, which offers consistent power supply. The manufacturing cost and electrochemical performance of a battery pack largely depends on the quality of the cathode material, which further depends on the production method and its parameters. However, the traditional stirred tank-based co-precipitation manufacturing process for precursors of lithium nickel manganese cobalt oxide (NCM111) cathode suffers from inhomogeneity in the reaction environment, which leads to non-uniform morphology and particle size distribution (PSD). In this work, slug-flow-based manufacturing platform, which offers a homogeneous reaction environment, is used for the continuous production of NCM111 oxalate precursors. One of the novel features of this work is the comparative study between the quality of batch and slug-flow-derived products. The slug-flow-derived product is found to be better in terms of having bigger particle size, narrower PSD and higher tap density. The study on the single and dual-element precipitation in similar conditions to understand the co-precipitation behavior in the slug-flow manufacturing platform is also a unique feature of this work. Furthermore, the effect of NH4OH concentration and residence time (RT) on the electrochemical performance of cathode were also studied and it is found that the cathode precursors synthesized at a NH4OH concentration of 0.08 M and a RT of 2 minutes followed by lithiation shows a better electrochemical performance of 128 mAh g−1 at 0.1 C with cycling stability of more than 80% both at 0.5 C and 1 C.

Morphology modification of LiNi0.5Co0.2Mn0.3O2 by incorporating cotton textiles in lithium-ion capacitors

To address the alerting issue of energy demand, lithium-ion capacitors (LICs) have been widely studied as promising electrochemical energy storage devices, which can deliver higher energy density than supercapacitors (SCs), and have higher power density with longer cycling life than lithium-ion batteries (LIBs). In this work, the active material lithium nickel cobalt manganese oxide LiNi0.5Co0.2Mn0.3O2 (NCM523) is grown on a cotton textile template and building a 3-dimensional (3D) integrity to improve capacitance and energy density of LICs by enhancing the interfacial ion-exchange process. With the 3D structure, the specific discharge capacitance is increased to 718.67 F g−1 at 0.1 A g−1 from that of non-textile NCM523 (265.97 F g−1), and remains a high capacitance of 254.48 Fg−1 at 10 A g−1 in the half-cell capacitors. In addition, the energy density can achieve up to 36.17 Wh kg−1 at the power density of 1,200 W kg−1 in the full-cell capacitor. The textile NCM can maintain an energy density of 28.26 Wh kg−1 at the current density of 10 A g−1 and power density of 6,000 W kg−1. Our results present promising applications of electrodes with the 3D porous structure for high energy density LICs.

Green recycling assessment on typical spent lithium-ion batteries (LIBs): A multi-objective assessment

Recycling of spent lithium-ion batteries (LIBs) is an efficient solution for resource supply crisis and severe environmental pollution. However, the comprehensive evaluation on resource criticality and environmental impact were neglected in the life cycle assessment (LCA). In this study, a green recycling assessment methodology was proposed associated with raw material criticality assessment, system operation elements analysis and comprehensive environmental assessment (CEA). The hydrometallurgical, pyrometallurgical and direct recycling process of lithium nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP) were selected as 6 typical recycling processes. Under the multi-objective assessment, the green recycling grades (G) was classified into 10 grades, and the direct recycling process of NMC and LFP were the two greenest recycling processes with the G value of 9.66 and 9.58. According to the assessment results of this study, direct recycling process was the best recycling process due to the less the consumption of substance and production of waste. This research established the green recycling assessment methodology for spent LIBs, which could guide the green development of spent LIBs recycling industry.

First-principles study of the structures and redox mechanisms of Ni-rich lithium nickel manganese cobalt oxides

To reduce the cobalt (Co) content in lithium-ion batteries, Ni-rich (high-Ni) lithium nickel manganese cobalt oxides (NMC) are pursued as one of the next-generation cathode materials. However, there is still debate on the crystal and electronic structures of the baseline, LiNiO2. Density Functional Theory (DFT) calculations were performed to provide a theoretical understanding of Ni-rich NMC. First, it was found that the commonly used R3¯m structure for LiNiO2 is metallic, contrary to the experimentally reported mix-conducting behavior. Among the four different space groups, R3¯m, C2/m, P21/c, and P2/c, P2/c with charge disproportionation of Ni2+ and Ni4+ is the most energetically stable and semiconducting structure of LiNiO2. Therefore, the atomic structures of representative Ni-rich NMC were built by partially replacing Ni with Co or Mn in the P2/c LiNiO2 to form LixNiyMnzCo1-y-zO2. In the fully lithiated (x = 1.0) high Ni content NMC (y > 0.5), the oxidation state of all Mn ions becomes 4+, while Co ions still maintain 3+, and part of the Ni ions become 2+ to compensate for the charge. Upon delithiation, the local environment shows more variation of the charge states on the transition metal (TM) ions. The average oxidation on each TM follows a sequence of losing electrons that starts from Ni2+ to Ni3+, then oxidizing Ni3+ and Co3+, while Mn4+ remains electrochemically inactive till x = 0. A general relationship for the oxidation state change in each TM as a function of x and y is derived and shows agreement with both modeling and experimental data.

Binary multi-frequency signal for accurate and rapid electrochemical impedance spectroscopy acquisition in lithium-ion batteries

Electrochemical Impedance Spectroscopy (EIS) plays a crucial role in characterizing the internal electrochemical states of lithium-ion batteries and proves to be effective for estimating battery states. Traditional EIS measurement, however, requires expensive electrochemical workstations with time-consuming signal injection, especially in low-frequency regions, thus limiting its practical applications. Here we show that applying our proposed pulse-like Binary Multi-Frequency Signals (BMFS) as the excitation signal in the EIS measurement, which simultaneously possesses numerous frequency components and maintains high energy at each frequency component, will significantly improve test speed while retaining accuracy. The applicability of the BMFS under various cathode material types, including nickel cobalt manganese (NCM), lithium cobalt oxide (LCO), and lithium iron phosphate (LFP) is demonstrated. The robustness of the signal is experimentally verified through varying C-rates and measurement window lengths. The BMFS, requiring only 30 s per test, can achieve test results with an amplitude error of 1% and a phase error of 1° as compared with those obtained from traditional EIS tests. Moreover, BMFS can also be applied in online EIS measurement scenarios, favorable for real-world applications. This work enables accurate and rapid acquisition of EIS results, which is currently expensive and time-consuming to obtain, ensuring a faster and more nuanced characterization of the internal states of many battery systems in an affordable and accessible manner, especially in data-driven and machine-learning approaches.