Xiao-Yu Wu

Lithium-ion batteries (LIBs) are pivotal in electric vehicles (EVs), grid storage, and portable electronics, but their high energy density introduces safety risks, particularly thermal runaway (TR). TR can lead to fires, explosions, and hazardous emissions, posing severe health and environmental threats. Experimental investigation of TR commonly relies on abuse testing methods, among which mechanical abuse via nail penetration (NP) and thermal abuse (TA) are widely used to simulate crash-induced and heat-driven failure scenarios, respectively. This review provides a comprehensive and comparative synthesis of NP and TA testing methodologies, examining how variations in test configuration, cell parameters (capacity, state of charge, and chemistry), and environmental conditions influence TR behavior and emission characteristics. Particular emphasis is placed on comparing reported emission profiles from NP- and TA-triggered TR events, including CO₂, CO, HF, hydrocarbons, and solvent vapors, and identifying the methodological origins of discrepancies across studies. By systematically linking emission variability to gas collection methods, analytical techniques, and data normalization approaches, this review highlights key limitations in current testing standards related to emission characterization. Finally, recommendations are offered for harmonizing abuse testing protocols and improving experimental design to enhance reproducibility, enabling meaningful cross-study comparison, and supporting safer deployment of LIBs in high-risk applications such as EVs and grid-scale energy storage.

Maintaining low oxygen partial pressure during ceria reduction is critical for efficient solar thermochemical fuel production, yet conventional routes rely on energy-intensive gas sweeping or vacuum pumping. We demonstrate a ceria-based reactor operated with a hybrid oxygen removal strategy; moderate sweep gas coupled with electrochemical oxygen pumping (SG + EOP), that enables in situ oxygen removal with reduced auxiliary energy. Increasing EOP’s operating potential from 0.5 to 1.0 V at moderate argon flow increased the molar oxygen production rate during reduction and led to a 15.6% increase in overall solar to fuel efficiency (from 0.307% to 0.355%). At these conditions, the EOP accounted for up to 12.1% of the total oxygen removal. Durable performance was demonstrated for over 102 redox cycles when controlled cooldown was ensured to prevent interfacial delamination. When scaling up to 500 kW, the lowest CO price was projected to be 1.19 $·kg ^-1 at the highest annual output (2.33 × 10 ⁴ kg·year ^-1 ) for SG + EOP compared to the SG and SG + VP (vacuum pump) method, establishing this hybrid approach as a practical and scalable pathway toward efficient and solar-to-fuel systems.

Rapid heating strategies are essential for the cold-start of lithium-ion batteries at subzero temperatures to avoid severe performance losses. This study explores different external and battery-powered heating strategies and evaluates the time required for 21700 lithium-ion battery modules to reach the minimum safe-operating temperature. Three heating strategies were simulated: battery discharge, external heating, and combined configurations at ambient temperatures of −20 to 0 °C with initial state of charges (SOCs) of 20–80%. Results show that with discharge-only heating, the module heated up slowly and was unable to completely discharge at −20 °C and 20% SOC. Yet when the external surface-heating strategy was applied, the module was heated up 75–86% faster to reach the safe-operating temperature, which allowed the module to discharge completely under all conditions. Furthermore, in a combined configuration strategy where the external surface-heating is applied while the module discharges, the module achieved an additional 7–21% faster temperature rise. Lastly, at −20 °C and 20% SOC, external heater energy exceeded the module’s usable output, while at 0 °C and moderate SOC, heater demand was only 2–3% of available battery capacity. Overall, findings show combining external heating discharge enables a reliable cold-start for the battery modules studied.

Solar thermochemical hydrogen (STCH) produced by heat-driven water-splitting is a promising route for producing green hydrogen and other zero-emission synfuels. However, the efficiency of STCH must be dramatically increased for it to make an impact on decarbonization efforts. We have previously presented a novel Reactor Train System (RTS) for significantly increasing the efficiency of STCH by employing heat recovery from the redox material and efficient gas exchange processes. In this paper we present a higher-fidelity model for the RTS that accommodates the slow heat diffusion through the STCH redox material. For this purpose, a novel method is introduced for transient modelling of radiative heat in participating media. This method, called GREENER: Generalized Radiation Exchange Factors and Net Radiation, combines the accuracy of Monte Carlo Ray Tracing with the low computational cost of the P1 or Rosseland diffusion approximations. Along with STCH, GREENER has application for modelling volumetric solar receivers, high temperature heat recovery systems like heat exchangers and regenerators, and packed bed reactors. Using the GREENER method, the RTS counterflow radiative heat exchanger is shown to achieve heat recovery effectiveness greater than 70%. The performance of non-uniform porous redox morphologies is evaluated, and high-performing configurations are identified.

Polyethylene oxide (PEO)‐based solid‐state batteries hold great promise as the next‐generation batteries with high energy density and high safety. However, PEO‐based electrolytes encounter certain limitations, including inferior ionic conductivity, low Li⁺ transference number, and poor mechanical strength. Herein, we aim to simultaneously address these issues by utilizing one‐dimensional zwitterionic cellulose nanofiber (ZCNF) as fillers for PEO‐based electrolytes using a simple aqueous solution casting method. Multiple characterizations and theoretical calculations demonstrate that the unique zwitterionic structure imparts ZCNF with various functions, such as disrupting PEO crystallization, dissociating lithium salts, anchoring anions through cationic groups, accelerating Li⁺ migration by anionic groups, as well as its inherent reinforcement effect. As a result, the prepared PL‐ZCNF electrolyte exhibits remarkable ionic conductivity (5.37×10⁻⁴ S cm⁻¹) and Li⁺ transference number (0.62) at 60 °C without sacrificing mechanical strength (9.2 MPa), together with high critical current density of 1.1 mA cm⁻². Attributed to these merits of PL‐ZCNF, the LiFePO₄|PL‐ZCNF|Li solid‐state full‐cell delivers exceptional rate capability and cycling performance (900 cycles at 5 C). Notably, the assembled pouch‐cell can maintain steady operation over 1000 cycles with an impressive 93.7 % capacity retention at 0.5 C and 60 °C, highlighting the great potential of PL‐ZCNF for practical applications.