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A Battery Electric Vehicle (BEV) pack requires an intelligent and integrated arrangement of the thermal management system (TMS). While previous studies have investigated TMSs independently, we here make a comparative analysis between air and immersion TMSs tailored for both sub-zero and peak summer temperatures, mimicking Nordic climate zones. A parametric sweep of flow and thermal design parameters using laminar and turbulent flow regimes is performed. These ambient conditions and loading pattern corresponding to a heavy BEV constitute the basis of the comparison. The analysis is based on various well-defined key performance indicators. Moreover, the air based TMS requires high Re flows to give the best performance, while immersion TMS can perform well in a laminar range. It was deduced that low Re (126) and high Re (>3000) may not give better thermal performance, and it is therefore crucial to design the TMS within the proposed flow and thermal design sets. In contrast to previous work, where the main focus has been on the cooling efficiency or steady-state performances, this work extends the horizon to investigate the effect of these TMSs on ageing behaviour to quantify long-term benefits on battery reliability and safety. The coupled ageing-thermal battery model was simulated for 1000 cycles for different cases, showcasing 3.4 % improvement in SOH for immersion TMS compared to the air based TMS. Thus, the climate resilient TMS aids in heat management, and the coupled model is thereby shown to help estimate the battery SOH.

Multivalent-ion batteries offer a sustainable, high-capacity alternative to lithium-ion systems, but their development is limited by the lack of electrolytes enabling efficient ion transport and stable interfaces. This study addresses these challenges by introducing three novel polyamine-type solid electrolytes (SPE) based on 4-amino-1,2,4-triazole units for Ca-ion and Zn-ion batteries. Synthesized under mild conditions (<70 °C) with excellent yields (98–99%), these materials were doped with Ca(TFSI)₂ or Zn(TFSI)₂ and integrated with a PTFE matrix to provide structural integrity and facilitate the formation of flexible, free-standing membranes, while also reducing interface impedance. The electrolytes exhibited high thermal stability (>250 °C) and promising ionic conductivities, with zinc-based systems (up to 0.12 mS·cm⁻¹) outperforming calcium analogues (1.4 × 10⁻³ mS·cm⁻¹).

To ensure these materials align with sustainability goals, the electrochemical characterization was complemented by a cradle-to-gate life cycle assessment. The analysis combined primary experimental data with background data from Ecoinvent v3.5. Global Warming Potential ranged from 4.9 × 10⁻² to 8.1 × 10⁻² kg CO₂-eq, with hydrazine use and electricity accounting for over 80% of total impacts. Electrolytes derived from alternative nitrile routes showed significantly lower carbon footprints than the succinonitrile-based counterpart, which, in turn, exhibited the highest ionic conductivity, highlighting a trade-off between environmental performance and electrochemical functionality. Beyond climate change, the succinonitrile-based formulation also showed the highest impacts across toxicity- and resource-related categories. Monte Carlo–based uncertainty analysis confirmed the robustness of these comparative results. Overall, this work introduces a new class of triazole-based SPEs while delivering early environmental insights to inform sustainable materials development in next-generation battery technology.

Mesoscale modeling of battery electrode materials requires accurate free energy data. Typical models employed assume the regular solution model, which accounts for ideal mixing entropy and weak interactions from the enthalpic contribution. However, this free energy description is insufficient when describing the LiFePO₄ electrode due to the electrostatic interactions between its ionic species. This study addresses the asymmetry in the experimental phase diagram of LiFePO₄, particularly the eutectoid point at 60% Li concentration, which the symmetric regular solution model fails to capture. We employ spline interpolations to capture this more complex free energy landscape within a phase-field model. Our findings reveal that when this asymmetry is accounted for, delithiation occurs through a solid solution pathway, driven by thermodynamic forces that induce an intermediate solid solution phase, thereby challenging the prevailing notion that this phase is only accessible at high charging rates at the nano-scale. The solid solution phase mitigates strain evolution and enhances delithiation rates compared to the conventional model, offering new insights into the phase transformation characteristics of LiFePO₄ electrodes.

The rapid increase in electric vehicle (EV) adoption has significantly boosted the demand for lithium-ion batteries (LIBs), creating an urgent need for sustainable recycling strategies. Discharging end-of-life LIBs is a critical preprocessing step before recycling. Electrical discharge via cables is the current industrial state of the art for large battery packs, whereas electrochemical discharge (discharging batteries in solutions) offers a reliable alternative for smaller and mixed waste streams. This study compares electrical and electrochemical discharge methods and examines their effects on the morphology and composition of electrode materials from spent LIBs. Additionally, it evaluates the potential of electrochemical discharge to enable a closed-loop direct recycling process by recovering high-quality active materials from spent LIBs. Characterization results reveal that the lithium content is higher on negative electrode sheets after electrical discharge than after electrochemical discharge. Unreacted lithium on Ni-rich layered oxides can form residual lithium compounds, such as lithium carbonate (Li2CO3) and lithium hydroxide (LiOH), which can trigger undesirable side reactions. PXRD analysis indicates that positive electrode materials subjected to electrochemical discharge retain their layered structure with minimal cation mixing, unlike those subjected to electrical discharge. Overall, the findings demonstrate that electrochemical discharge is more effective in preserving the chemical composition and structural integrity of active materials than conventional electrical discharge methods.

Solid state lithium batteries appear as viable options for next-generation energy storage systems addressing the issues related to the safety risks associated with conventional liquid electrolytes. The use of inorganic fillers in polymer electrolyte matrices significantly boost battery performance, making composite polymer electrolytes (CPEs) a subject of growing interest. This study serves as a proof of concept, investigating lithium phosphate (Li₃PO₄) as a reinforcing agent in poly(ethylene oxide)-lithium bis(trifluoromethanesulfonyl)imide (PEO-LiTFSI) electrolytes. A range of composite electrolytes with varying Li₃PO₄ concentrations (0-30 wt%) were prepared using solvent casting. The addition of Li₃PO₄ markedly improved the electrochemical properties, with the 20 wt% composition demonstrating the highest lithium-ion transference number (T₊ ∼0.33 at 60°C) and ionic conductivity (6.59 x 10^-5 S/cm at 60°C), as well as extended electrochemical stability up to 5.2 V. Despite its higher degree of crystallinity, this composition exhibited useful cycling stability in Li|Li cells for over 400h, attributed to improved interfacial contacts and mechanical properties, inhibiting lithium filaments growth. When tested in an NMC₈₁₁cell configuration, the composite electrolyte displayed stable cycling performance, achieving a coulombic efficiency of 95 %. These results advance the development of phosphate-based composite polymer electrolytes for safer, high-performance solid-state lithium batteries.

To advance the electrification of the transport sector beyond passenger cars, electrifying heavy-duty trucks is essential. These vehicles typically use prismatic lithium-ion cells arranged in modules, separated by heat-insulating thermal pads that enhance safety during thermal runaway (TR). In this study, we developed and applied a method to map heat flow through various paths during TR propagation across three test cases with different thermal pads. The results were quantitatively evaluated using Sankey diagrams, a novel approach in this context. Using this method, we measured in situ thermal conductivity and found significant differences from standard reference values. As expected, lower in situ thermal conductivity increased the delay in thermal propagation. However, the method revealed that while the thermal pad remains the primary heat flow path during TR propagation, other contributors become significant if the pad has sufficiently low thermal conductivity. This finding is noteworthy, as the pad with the lowest conductivity nearly stops the propagation altogether, and attention to the other paths could be the key to achieving a full stop. We conclude that by investigating thermal pads under operational conditions, this study provides valuable insights into critical heat transfer paths and failure mechanisms, offering guidance on optimizing battery safety and lifespan.

Thermal runaway (TR) and its propagation (TRP) pose critical risks in the application of large-format lithium-ion batteries in heavy-duty electric vehicles. In this work, we apply a computational approach using a lumped heat release model. This model is calibrated with experimental data from accelerating rate calorimetry (ARC) and TRP tests to investigate battery aging effects on TR and TRP. It is seen that the simulations can effectively reproduce key experimental observations, such as TR onset temperature, maximum temperature, and TRP time. Furthermore, the influence of battery aging on TR behavior is investigated, specifically solid–electrolyte interphase (SEI) growth and electrolyte decomposition. The findings reveal that aging significantly accelerates TR onset while lowering the heat release of batteries. The interplay between accelerated SEI layer growth and electrolyte decomposition significantly influences TRP dynamics. Compared to new batteries, the total TRP time initially decreases during early aging, reaching 78% of the original TRP time at around 80% state of health (SOH). During late aging, TRP time slightly increases to 85% of the original time at 50% SOH. This computational approach provides crucial insights into the dynamic safety of aged batteries with regard to different combinations of electrolyte decomposition and SEI thickness growth rate.

Silicon-based anodes offer substantially higher theoretical capacities than graphite in lithium-ion batteries, but their practical deployment is hindered by severe volume changes that induce mechanical degradation and unstable interfacial chemistry. While nanoscaling strategies can mitigate these effects, they often suffer from low tapped density, complex synthesis, and limited scalability. Porous silicon microparticles provide a promising alternative by partially accommodating volume expansion while preserving processability and electrode-level integrity. Here, a HF-free urea-assisted etching strategy is employed to generate porous silicon microparticles under mild conditions, leveraging the coupled action of thermally induced structural disruption and chemically driven surface modification. Control experiments confirm that the combined action of these effects is essential to achieve BJH-resolved mesoporosity and increased surface area. The resulting porous silicon exhibits oxygen- and nitrogen-containing surface functionalities. Composite electrodes prepared with nanographite and sodium alginate binder at graphite:silicon:binder ratios of 8:1:1, 7:2:1, and 4.5:4.5:1 demonstrate improved electrochemical behavior. In half-cell testing, electrodes containing 10-20 wt % porous silicon deliver stable redox activity and retain 630-880 mAh g^-1 after 100 cycles at 0.1 C, with Coulombic efficiencies of 98.8-99.7%, whereas higher silicon loadings lead to rapid capacity decay. Cycling-resolved impedance and differential-capacity analyses reveal the formation of a thicker yet mechanically resilient interphase that stabilizes charge-transfer kinetics, while rate capability tests show 65-74% capacity retention at 2 C.

Constructing mechanically stable interphases is a prerequisite for practical lithium metal batteries. Interphases formed via direct reaction with metallic lithium are promising, yet they typically suffer from structural instability arising from severe volume expansion and the pulverization of coarse grains driven by Ostwald ripening. Herein, we present a strategy to suppress particle coarsening during in situ interphase formation by simultaneously tuning the reduction potentials of metal precursors and the lattice mismatch between resulting metals. We demonstrate that electrochemical co-reduction boosts local supersaturation to achieve uniformly distributed nuclei, while a large lattice mismatch drives the formation of thermodynamically stable intermetallic compounds. Together, these effects yield a dense, nanoscale alloy interphase. As a proof of concept, the co-reduction of tin(II) fluoride and antimony(III) fluoride produces grain-refined tin-antimony that undergoes only 2.2% lateral size expansion during cycling compared with the Sn interphase (24.8%) as confirmed by in situ electrochemical transmission electron microscopy. Consequently, a 0.3 Ah pouch cell retains 92% capacity after 200 cycles, and a 5.4 Ah pouch cell achieves high energy density of 530 Wh kg^-1. This work sheds light on the multimetal co-reduction as a screening principle for constructing interphases on metallic-based electrodes.

All-solid-state Li-metal batteries (ASSLMBs) using poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) offer enhanced safety and energy density compared to conventional liquid electrolytes. However, residual water uptake by hygroscopic PEO remains a critical yet largely underexplored issue. In this study, density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations were employed to investigate the interactions between water and PEO oligomers, the impact of water on Li⁺ solvation structures, and the interfacial decomposition mechanisms on Li-metal anodes for SPEs. Analysis of the electronic properties of a PEOwater complex revealed strong OH···O hydrogen bonds. AIMD simulations of a water-containing SPE showed that water oxygen atoms enter the first Li⁺ solvation sheath, reducing the coordination number of TFSI anions and potentially weakening anion-derived SEI formation. On the Li surface, AIMD trajectories and DFT calculations reveal two primary water-decomposition pathways: direct O-H cleavage yielding LiOH and Li_xH, and surface-hydrogen attack producing H₂ and LiOH, both of which are thermodynamically and kinetically favorable. Finally, atomic charge distribution characterization of interphase components revealed that watercontaining SPEs yield fewer inorganic species compared to water-free SPEs. This study highlights the necessity of applying stringent drying pretreatment to PEO-based SPEs for achieving high-performance ASSLMBs.