Hadi Khani

ABSTRACT Thermochemical characterization of battery materials links intrinsic material properties to decomposition pathways, heat generation, and gas evolution that govern performance and safety. Despite extensive work on NMC811‐Graphite, variability across partial configurations and the limited adoption of micro‐cell architectures (cathode+anode+electrolyte+separator) hinder robust cell‐scale interpretation. Accordingly, this work establishes a bottom‐up, component‐resolved methodology integrating DSC/TGA, evolved gas analysis (EGA), and in situ XRD to link decomposition pathways and energy release across partial and micro‐cell configurations, providing a transferable assessment of safety and stability in emerging chemistries. In separator‐free configurations, the gas–solid reaction between cathode‐evolved and anode‐leached Li dominates the net heat release (1139 J ). In contrast, in the micro‐cell configuration, the separator hinders transport and alters the timing and pathways of other reactions, and reduces the net energy release to 618 J . Energy release was organized into defined temperature windows that provide a framework for a thermodynamic model combining quantified gas evolution with selected decomposition pathways and effective reaction enthalpies to estimate net specific energy release, with agreement between DSC and cell‐level tests. Ex situ XPS of heat‐treated samples extends post‐mortem analysis to thermal‐abuse regimes, supporting key pathway elements.

Electrification of transportation and grid-scale renewable energy storage are driving an unprecedented demand for energy storage solutions. Next-generation (next-gen) battery technologies, including the use of alternatives to commercial graphite anode materials and solid-state electrolytes, offer the potential for enhanced performance compared to conventional lithium-ion batteries (LIBs). Recent research has shown that ultrasonic inspection methods provide insightful understanding of mechanical property changes that occur in lithium-ion batteries with different lithiation and aging states. This work presents preliminary research that extends the use of ultrasonic methods for next-gen batteries and compares the observations with those in conventional LIBs. We investigate contact and immersion ultrasonic testing methods to monitor the evolution of time-domain characteristics (e.g., time of flight, amplitude) and frequency-domain metrics (e.g., spectral content, attenuation) under various cycling conditions and thermal loading. By tracking these metrics, we intend to get insights into changes in mechanical properties associated with electrochemical behavior unique to next-gen cells. Ultrasonic immersion imaging provides insights into spatial heterogeneities of the inspected cells subjected to the same loading processes. These experiments, paired with physical modeling of wave phenomena in these systems, provide a framework for comparing next-gen batteries to traditional LIBs and provide insight into their unique chemistries.

In lithium-ion battery manufacturing, following electrode preparation and cell assembly, electrolyte filling and wetting is a critical and throughput-determining step that often takes tens of hours due to the slow electrolyte infiltration of porous electrodes. This prolonged wetting process significantly limits production efficiency and increases manufacturing costs, highlighting the need for more effective electrolyte wetting strategies. In this study, we investigated the electrolyte wetting behavior of 2 Ah LiFePO 4 (LFP)–graphite (Gr) pouch cells using ultrasonic transmission imaging and electrochemical impedance spectroscopy. Although elevated temperature can moderately accelerate electrolyte wetting, the improvement remains insufficient for practical production. Inspired by the sponge-like absorption behavior in the densely packed, highly tortuous, and irregular porous structures, we developed a pulsed pressurizing strategy that applies intermittent mechanical pressure to promote electrolyte penetration, successfully reducing the impregnation time to within 1 h. Electrochemical cycling tests further confirm that applying pressure during wetting does not compromise battery performance. This work offers a practical and scalable solution to significantly shorten electrolyte wetting time and accelerate the overall production process of lithium-ion batteries.

Battery operation involves sophisticated spatiotemporal evolutions that critically govern their behaviors and degradation. Understanding and manipulating structural heterogeneity and chemical dynamics are key to improving battery performance, lifespan, and safety. This review examines spatial heterogeneity across multiple scales and explores the temporal asynchronicity characteristics of lithium-ion batteries. Furthermore, it underscores the importance of multimodal, high-throughput, and in-situ/operando characterization techniques, paired with advanced data mining methods, in advancing knowledge of battery evolution. We intend for this review to provide a systematic perspective on the spatiotemporal evolution of batteries and to inspire further research into its implications for next-generation battery research and development.

Operando Raman spectroscopy detects subtle structural evolutions, often obscured by XRD due to low scattering by elements like C and N and XRD's averaging nature, offering deeper insight into insertion mechanisms in Prussian blue analogue cathodes.

Highly conductive TiNb 2 O 6.93 , synthesized in under 60 seconds, features oxygen deficiencies at edge-shared octahedra and enlarged d -spacing. With a lithiated polyacrylic acid binder, it accommodates >3 Li + ions without electrolyte decomposition.

Abstract Garnet‐type Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (LLZTO) solid electrolytes provide the necessary electrochemical stability and ionic conductivity for solid‐state lithium‐metal batteries (SSLMBs). However, their wider application is hindered by their high interfacial resistance with electrodes and a lengthy synthesis process. This study presents the synthesis of densified LLZTO electrolytes using unconventional Li 2 O and Li 2 ZrO 3 precursors through an ultrafast (≈60 s) Joule heat‐assisted synthesis approach in a single‐step process. The lower sintering temperature of Li 2 ZrO 3 compared to traditional ZrO 2 precursor yields LLZTO with larger grains, resulting in enhanced Li + conductivity (7.0 × 10 −4 S cm −1 at 25 °C), reduced electronic conductivity (1.7 × 10 −10 S cm −1 ), and higher density (94.2%). Applying a 52–80 nm Sn:SnF 2 coating on the LLZTO surface using a melt‐quenching approach produces a uniform interlayer that chemically converts to Li‐Sn alloy and LiF upon contact with lithium, resulting in a near‐zero interfacial resistance and a critical current density of 4.2 mA cm −2 at 25 °C. The SSLMBs, incorporating Sn:SnF 2 ‐coated LLZTO electrolyte with NMC811 cathode, demonstrate remarkable initial capacity (181.1 mAh g −1 ) and cycle performance (88.63% capacity retention at 3000th cycle). The results indicate that this approach has the potential to advance the commercial fabrication technology for high‐performance solid electrolytes for SSLMBs.

Single-ion (Li + ) conducting electrolytes with a high Li + conductivity and transference number (LTN) are promising electrolyte candidates for eliminating the concentration polarization and inhibiting the growth of lithium dendrites in lithium-metal batteries at high power and energy densities. This study presents the synthesis and electrochemical characterization of an AB-type single-ion Li + conducting polymer consisting of a perfluorinated lithium-salt monomer (A) covalently bonded to a polyethylene glycol monomer (B). An investigation into several plasticizers reveals that ether-based solvents with moderate dielectric constants significantly enhance the Li + conductivity of single-ion (Li + ) conducting gel polymer electrolytes (SIC-GPE) while also maintaining the mechanical integrity of SIC-GPE. The perfluorinated lithium-salt units with weakly coordinating anions provide the advantage of high Li + conductivity (1.1 × 10 –4 S cm –2 ) and transference number (0.92), while polyethylene glycol units contribute to high flexibility and enhance plasticizer wettability in the SIC-GPE. The interfacial stability and electrochemical performance of SIC-GPE are demonstrated in lithium-metal symmetric cells (maintaining stability for >1300 h at 1 mAh cm –2 ) and lithium-metal batteries (retaining 98% capacity after 200 cycles).

Abstract The identity of alkali metal cations in the electrolyte of electrocatalysis systems has been recently introduced as a crucial factor to tailor the kinetics and Faradaic efficiency of many electrocatalytic reactions. In this Minireview, we have summarized the recent advances in the molecular‐level understanding of cation effects on relevant electrocatalytic processes such as hydrogen evolution (HER), oxygen evolution (OER), and CO 2 electroreduction (CO 2 RR) reactions. The discussion covers the effects of electrolyte cations on interfacial electric fields, structural organization of interfacial water molecules, blocking the catalytic active sites, stabilization or destabilization of intermediates, and interfacial pHs. These cation‐induced interfacial phenomena have been reported to impact the performance (activity, selectivity, and stability) of electrochemical reactions collaboratively or independently. We describe that although there is almost a general agreement on the relationship between the size of alkali cations and the activities of HER, OER, and CO 2 RR, however, the mechanism by which the performance of these electrocatalytic reactions is influenced by alkali metal cations is still in debate.

Abstract The identity of alkali metal cations in the electrolyte of electrocatalysis systems has been recently introduced as a crucial factor to tailor the kinetics and Faradaic efficiency of many electrocatalytic reactions. In this Minireview, we have summarized the recent advances in the molecular‐level understanding of cation effects on relevant electrocatalytic processes such as hydrogen evolution (HER), oxygen evolution (OER), and CO 2 electroreduction (CO 2 RR) reactions. The discussion covers the effects of electrolyte cations on interfacial electric fields, structural organization of interfacial water molecules, blocking the catalytic active sites, stabilization or destabilization of intermediates, and interfacial pHs. These cation‐induced interfacial phenomena have been reported to impact the performance (activity, selectivity, and stability) of electrochemical reactions collaboratively or independently. We describe that although there is almost a general agreement on the relationship between the size of alkali cations and the activities of HER, OER, and CO 2 RR, however, the mechanism by which the performance of these electrocatalytic reactions is influenced by alkali metal cations is still in debate.

Abstract All‐solid‐state lithium‐metal batteries offer higher energy density and safety than lithium‐ion batteries, but their practical applications have been pushed back by the sluggish Li + transport, unstable electrolyte/electrode interface, and/or difficult processing of their solid‐state electrolytes. Li + ‐conducting composite polymer electrolytes (CPEs) consisting of sub‐micron particles of an oxide solid‐state electrolyte (OSSE) dispersed in a solid, flexible polymer electrolyte (SPE) have shown promises to alleviate the low Li + conductivity of SPE, and the high rigidity and large interfacial impedance of OSSEs. Solution casting has been by far the most widely used procedure for the preparation of CPEs in research laboratories; however, this method imposes several drawbacks including particle aggregation and settlement during a long‐term solvent evaporation step, excessive use of organic solvents, slow production time, and mechanical issues associated with handling of ultra‐thin films of CPEs (<50 µm). To address these challenges, an electrophoretic deposition (EPD) method is developed to in situ deposit ultra‐thin CPEs on lithium‐iron‐phosphate (LFP) cathodes within just a few minutes. EPD‐prepared CPEs have shown better electrochemical performance in the lithium‐metal battery than those CPEs prepared by solution casting due to a better dispersion of OSSE within the SPE matrix and improved CPE contact with LFP cathodes.

Abstract A solid‐state battery with a lithium‐metal anode and a garnet‐type solid electrolyte has been widely regarded as one of the most promising solutions to boost the safety and energy density of current lithium‐ion batteries. However, lithiophobic property of garnet‐type solid electrolytes hinders the establishment of a good physical contact with lithium metal, bringing about a large lithium/garnet interfacial resistance that has remained as the greatest issue facing their practical application in solid‐state batteries. Herein, a melt‐quenching approach is developed by which varieties of interfacial modification layers based on metal alloys can be coated uniformly on the surface of the garnet. It is demonstrated that with an ultrathin, lithiophilic AgSn 0.6 Bi 0.4 O x coating the interfacial resistance can be eliminated, and a dendrite‐free lithium plating and stripping on the lithium/garnet interface can be achieved at a high current density of 20 mA cm −2 . The results reveal that the uniform coating on the garnet surface and the facile lithium diffusion through the coating layer are two major reasons for the excellent electrochemical performances. The all‐solid‐state full cell consisting of the surface modified garnet‐type solid electrolyte with a LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode and a lithium–metal anode maintains 86% of its initial capacity after 1000 stable cycles at 1 C.