Non-destructive characterization techniques for battery performance and lifecycle assessment

As global energy demands escalate, and the use of non-renewable resources become untenable, renewable resources and electric vehicles require far better batteries to stabilize the new energy landscape. To maximize battery performance and lifetime, understanding and monitoring the fundamental mechanisms that govern their operation throughout their life cycle is crucial. Unfortunately, from the moment batteries are sealed until their end-of-life, they remain a black box, and our current knowledge of a commercial battery s health status is limited to current (I), voltage (V), temperature (T), and impedance (R) measurements, at the cell or even module level during use. Electrochemical models work best when the battery is new, and as state reckoning drifts leading to an over-reliance on insufficient data to establish conservative safety margins resulting in the systematic under-utilization of cells and batteries. While the field of operando characterization is not new, the emergence of techniques capable of tracking commercial battery properties under realistic conditions has unlocked a trove of chemical, thermal, and mechanical data that has the potential to revolutionize the development and utilization strategies of both new and used lithium-ion devices. In this review, we examine the latest advances in non-destructive operando characterization techniques, including electrical sensors, optical fibers, acoustic transducers, X-ray-based imaging and thermal imaging (IR camera or calorimetry), and their potential to improve our comprehension of degradation mechanisms, reduce time and cost, and enhance battery performance throughout its life cycle

Insights into lithium inventory quantification of LiNi_0.5Mn_1.5O₄–graphite full cells

High voltage spinel cathode LiNi0.5Mn1.5O4 (LNMO) offers higher energy density and competitive cost compared to traditional cathodes in lithium-ion batteries, making it a promising option for high-performance battery applications. However, the fast capacity decay in full cells hinders further commercialization. The Li inventory evolution upon cycling in the LNMO–graphite pouch cell is systematically studied by developing lithium quantification methods on the cathode, anode, and electrolyte. The findings reveal that active Li loss is a primary factor contributing to capacity decay, stemming from an unstable anode interphase caused by crosstalk. This crosstalk primarily originates from electrolyte degradation on the cathode under high-voltage operation, leading to increased moisture and acidity, subsequently corroding the anode interphase. In response, two approaches including an aluminum oxide (Al2O3) surface coating layer on the cathode and lithium difluoro(oxalato)borate (LiDFOB) electrolyte additives are evaluated systematically, resulting in cycling stability enhancement. This study offers a quantitative approach to understanding the Li inventory loss in the LNMO–Gr system, providing unique insights and guidance into identifying critical bottlenecks for developing high voltage (>4.4 V) lithium battery technology

Elucidating the Role of Prelithiation in Si-based Anodes for Interface Stabilization

Prelithiation as a facile and effective method to compensate the lithium inventory loss in the initial cycle has progressed considerably both on anode and cathode sides. However, much less research has been devoted to the prelithiation effect on the interface stabilization for long-term cycling of Si-based anodes. An in-depth quantitative analysis of the interface that forms during the prelithiation of SiOx is presented here and the results are compared with prelithiaton of Si anodes. Local structure probe combined with detailed electrochemical analysis reveals that a characteristic mosaic interface is formed on both prelithiated SiOx and Si anodes. This mosaic interface containing multiple lithium silicates phases, is fundamentally different from the solid electrolyte interface (SEI) formed without prelithiation. The ideal conductivity and mechanical properties of lithium silicates enable improved cycling stability of both prelithiated anodes. With a higher ratio of lithium silicates due to the oxygen participation, prelithiated SiO1.3 anode improves the initial coulombic efficiency to 94% in full cell and delivers good cycling retention (77%) after 200 cycles. The insights provided in this work can be used to further optimize high Si loading (>70% by weight) based anodes in future high energy density batteries

Key Parameters in Determining the Reactivity of Lithium Metal Battery

Lithium metal anodes are crucial for high-energy-density batteries, but concerns regarding their safety remain. Limited investigations have evaluated the reactivity of Li metal anodes in full cell configurations. In this study, differential scanning calorimetry (DSC) and in situ Fourier-transform infrared spectroscopy (FTIR) were employed to quantitatively examine the Li metal reactivity. Lithiated graphite (Li-Gr) and lithiated silicon (Li-Si) were also compared. The reactivity of plated Li was systematically investigated when combined with different electrolyte compositions, morphologies, atmospheres, and various cathode materials (NMC622, LFP, and LNMO). It was discovered that all cell components, such as electrolyte composition, Li morphology, control of inactive Li accumulation, and cathode stability, play essential roles in regulating the reactivity of the plated Li. By optimizing these factors, the Li metal full cell exhibited no significant thermal reaction up to 400 °C. This research identifies key parameters for controlling Li metal reactivity, potentially advancing lithium metal battery design and manufacturing

Key Parameters in Determining the Reactivity of Lithium Metal Battery

Lithium metal anodes are crucial for high-energy-density batteries, but concerns regarding their safety remain. Limited investigations have evaluated the reactivity of Li metal anodes in full cell configurations. In this study, differential scanning calorimetry (DSC) and in situ Fourier-transform infrared spectroscopy (FTIR) were employed to quantitatively examine the Li metal reactivity. Lithiated graphite (Li-Gr) and lithiated silicon (Li-Si) were also compared. The reactivity of plated Li was systematically investigated when combined with different electrolyte compositions, morphologies, atmospheres, and various cathode materials (NMC622, LFP, and LNMO). It was discovered that all cell components, such as electrolyte composition, Li morphology, control of inactive Li accumulation, and cathode stability, play essential roles in regulating the reactivity of the plated Li. By optimizing these factors, the Li metal full cell exhibited no significant thermal reaction up to 400 °C. This research identifies key parameters for controlling Li metal reactivity, potentially advancing lithium metal battery design and manufacturing

Quantitatively Designing Porous Copper Current Collectors for Lithium Metal Anodes

International audienceLithium metal has been an attractive candidate as a next-generation anode material. Despite its popularity, stability issues of lithium in the liquid electrolyte and the formation of lithium whiskers have kept it from practical use. Three-dimensional (3D) current collectors have been proposed as an effective method to mitigate whisker growth. Although extensive research has been done, the effects of three key parameters of the 3D current collectors, namely, the surface area, the tortuosity factor, and the surface chemistry, on the performance of lithium metal batteries remain elusive. Herein, we quantitatively studied the role of these three parameters by synthesizing four types of porous copper networks with different sizes of well-structured microchannels. X-ray microscale computed tomography (micro-CT) allowed us to assess the surface area, the pore size, and the tortuosity factor of the porous copper materials. A metallic Zn coating was also applied to study the influence of surface chemistry on the performance of the 3D current collectors. The effects of these parameters on the performance were studied in detail through scanning electron microscopy (SEM) and titration gas chromatography (TGC). Stochastic simulations further allowed us to interpret the role of the tortuosity factor in lithiation. The optimal range of the key parameters is thereby found for the porous coppers and their performance is predicted. Using these parameters to inform the design of porous copper anodes for Li deposition, Coulombic efficiencies (CEs) of up to 99.63% are achieved, thus paving the way for the design of effective 3D current collector systems

Carbon Free High Loading Silicon Anodes Enabled by Sulfide Solid Electrolytes for Robust All Solid-State Batteries

The development of silicon anodes to replace conventional graphite in efforts to increase energy densities of lithium-ion batteries has been largely impeded by poor interfacial stability against liquid electrolytes. Here, stable operation of 99.9 weight% micro-Si (uSi) anode is enabled by utilizing the interface passivating properties of sulfide based solid-electrolytes. Bulk to surface characterization, as well as quantification of interfacial components showed that such an approach eliminates continuous interfacial growth and irreversible lithium losses. In uSi || layered-oxide full cells, high current densities at room temperature (5 mA cm 2), wide operating temperature (-20{\deg}C to 80{\deg}C) and high loadings (>11 mAh cm-2) were demonstrated for both charge and discharge operations. The promising battery performance can be attributed to both the desirable interfacial property between uSi and sulfide electrolytes, as well as the unique chemo-mechanical behavior of the Li-Si alloys

Carbon Free High Loading Silicon Anodes Enabled by Sulfide Solid Electrolytes for Robust All Solid-State Batteries

The development of silicon anodes to replace conventional graphite in efforts to increase energy densities of lithium-ion batteries has been largely impeded by poor interfacial stability against liquid electrolytes. Here, stable operation of 99.9 weight% micro-Si (uSi) anode is enabled by utilizing the interface passivating properties of sulfide based solid-electrolytes. Bulk to surface characterization, as well as quantification of interfacial components showed that such an approach eliminates continuous interfacial growth and irreversible lithium losses. In uSi || layered-oxide full cells, high current densities at room temperature (5 mA cm 2), wide operating temperature (-20{\deg}C to 80{\deg}C) and high loadings (>11 mAh cm-2) were demonstrated for both charge and discharge operations. The promising battery performance can be attributed to both the desirable interfacial property between uSi and sulfide electrolytes, as well as the unique chemo-mechanical behavior of the Li-Si alloys

Carbon-free high-loading silicon anodes enabled by sulfide solid electrolytes.

The development of silicon anodes for lithium-ion batteries has been largely impeded by poor interfacial stability against liquid electrolytes. Here, we enabled the stable operation of a 99.9 weight % microsilicon anode by using the interface passivating properties of sulfide solid electrolytes. Bulk and surface characterization, and quantification of interfacial components, showed that such an approach eliminates continuous interfacial growth and irreversible lithium losses. Microsilicon full cells were assembled and found to achieve high areal current density, wide operating temperature range, and high areal loadings for the different cells. The promising performance can be attributed to both the desirable interfacial property between microsilicon and sulfide electrolytes and the distinctive chemomechanical behavior of the lithium-silicon alloy