Lang Huang

The elevated temperature cycle life of high specific energy lithium-ion batteries (LIBs) employing SiO _x -containing anodes and high-nickel cathodes is critically limited by the thermal instability of conventional LiPF ₆ -carbonate electrolytes. Wherein, fluoroethylene carbonate (FEC), an essential additive or co-solvent for stabilizing SiO _x -containing anodes, undergoes deleterious hydrolysis and PF ₅ -catalyzed ring-opening polymerization at elevated temperatures, producing additional corrosive HF and viscous polymeric species that impede Li ⁺ transport. Herein, the coupled degradation pathways of FEC-assisted LiPF ₆ -carbonate electrolytes are elucidated, with the Lewis acid PF ₅ and trace H ₂ O identified as the principal culprits driving FEC degradation at elevated temperatures. Distinguished from carbon-intensive supercomputing simulations or wasteful trial-and-error synthesis, we leverage a resource-efficient and physics-informed high-throughput screening workflow capable of running on a standard desktop computer within minutes to pinpoint a top-ranked cyano-enriched additive of lithium bis(1,2-dihydroxyethane-1,1,2,2-tetranitrile)borate (LiBTCB) from a library of 1,446,718 molecules. The selected critical physicochemical descriptors place particular emphasis on hydrophilic scavenging efficiency for moisture removal and on effective Lewis basicity for PF ₅ complexation. Subsequently, the top-ranked LiBTCB additive is synthesized and found to possess exceptional affinity for PF ₅ and H ₂ O, thereby suppressing HF formation, inhibiting FEC polymerization, and stabilizing the bulk electrolyte. More encouragingly, the additive combination of FEC and LiBTCB enables a high specific energy battery system of LiNi _0.8 Co _0.1 Mn _0.1 O ₂ /SiO _x -Graphite with unprecedented high capacity retention of 80.9% after 600 cycles at 50 °C. It is also disclosed that this additive combination contributes to construct robust interphases on both electrodes. This research underscores the great importance of low-carbon and computation-efficient machine learning assisted additives molecular design in tailoring electrolytes and interphases for next generation LIBs with high specific energy density.

To advance toward commercial viability, sodium-ion batteries are required to operate under high cut-off voltages and low temperatures. This necessitates electrolyte designs that provide sufficient oxidative stability for high-voltage cycling while maintaining high ion mobility at low temperatures. Herein we design a non-flammable sulfonamide solvent molecule, N-ethyl-N-methyl-trifluoromethanesulfonamide, by introducing asymmetric alkyl substituents that create a geometric kink to hinder efficient crystal packing during cooling, leading to a low melting point (−86 °C). The resulting sulfonamide-based electrolyte exhibits weak ion–dipole interaction and favorable solvation structures enriched in contact ion pairs and aggregates, which promote the formation of highly stable and conductive interphases with both the positive and negative electrodes. Benefiting from these features, the sulfonamide-based electrolyte enables 1-Ah-level hard carbon||NaNi _1/3 Fe _1/3 Mn _1/3 O ₂ pouch cells to retain 69.8% and 42.3% of room-temperature capacity even at −60 °C and −70 °C, while achieving capacity retentions of 90.0% and 81.6% after 1500 and 1000 cycles at high upper cut-off voltages of 4.15 V and 4.2 V, respectively. The sulfonamide-based electrolyte also improves the high-temperature cycling stability and delays the onset and trigger of thermal runaway at the pouch-cell level. This work offers fundamental insights into solvent molecule and electrolyte design for advancing high-energy and wide-temperature sodium-ion batteries.

Sulfide all solid-state batteries represent a promising next generation energy storage technology. However, their presumed safety is challenged by the risk of thermal runaway initiating at unexpectedly low temperatures. This critical issue stems from the unstable chemical interface between the positive electrode and thiophosphate solid electrolyte, a factor often overlooked in favor of electrochemical studies. Here we demonstrate that this electrochemically formed interphase is the primary trigger for catastrophic failure, not the bulk materials. Our investigation reveals a universal two stage degradation mechanism. The first stage involves intense exothermic reactions at the interface below 160 °C, releasing heat and gases. This initiates a second stage of propagating reactions leading to thermal runaway. Crucially, we show this hazardous process can be suppressed by interface engineering. We design a stable interfacial layer using a germanium sulfur chemistry, specifically lithium germanium sulfide. This modification delivers improved thermal safety without sacrificing battery performance. Our findings have the potential to establish a forward-looking safety paradigm, shifting the focus from bulk material compatibility to interfacial stability, and provide a vital design principle for future safe solid-state batteries.

We revealed the mechanical design requirements for low-stack-pressure Si-based solid-state anodes. We demonstrated a low-pressure operation (2 MPa) by introducing a mechanically heterogeneous alloy.

Electrolyte optimization is recognized as a critical strategy for enhancing both the long-term cycling stability and safety performance of lithium-ion batteries.

Ni-rich layered oxide cathodes have garnered considerable attention for their high energy density but suffer from notorious safety concerns in lithium-ion batteries (LIBs). During thermal runaway (TR) of LIBs, the cathode surface induced electrolyte decomposition and oxygen release from bulk crystal structure transitions are both responsible for accelerating the rapid self-heating, yet their specific roles and contributions have never been explicitly elucidated, leaving uncertainty of safety enhancing strategies regarding bulk crystal structure modification versus interphase regulation. Here, we systematically analyzed the thermal runaway characteristics of varied Ni-rich layered cathode LIBs, from cell level to material level. Quantificational comparisons between the TR temperature of LIBs and phase transition point of cathode materials reveal that for ultrahigh Ni (≥80%) cathode LIBs, exothermic interfacial parasitic reactions dominate the TR process, while for those with relatively low Ni content (≤60%), it is the O₂ escaping from the phase transition and the following oxidization it involves that govern the TR behavior. Moreover, the underlying reaction pathways of cathode/electrolyte reactions are explored in detail by deconvoluting the electrochemical–thermo–mechanical evolution process during TR. Stress accumulation from phase inhomogeneity aggravates interfacial reaction and gassing, while the gaseous species trapped in turn drives crack propagation upon temperature argument, constituting a self-sustaining loop consequently developing into catastrophic TR. This work bridges a critical knowledge gap in understanding the correlation between TR performance and microstructures, and highlights the necessity of promoting interfacial compatibility for safe Ni-rich cathode LIBs.

Gas evolution in lithium-ion batteries represents a pivotal yet underaddressed concern, significantly compromising long-term cyclability and safety through complex interfacial dynamics and material degradation across both normal operation and extreme thermal scenarios. While extensive research has focused on isolated gas generation mechanisms in specific components, critical knowledge gaps persist in understanding cross-component interactions and the cascading failure pathways it induced. This review systematically decouples gas generation mechanisms at cathodes (e.g., lattice oxygen-driven CO₂/CO in high-nickel layered oxides), anodes (e.g., stress-triggered solvent reduction in silicon composites), electrolytes (solvent decomposition), and auxiliary materials (binder/separator degradation), while uniquely establishing their synergistic impacts on battery stability. Distinct from prior modular analyses, we emphasize that: (1) emerging systems exhibit fundamentally different gas evolution thermodynamics compared to conventional materials, exemplified by sulfide solid electrolytes releasing H₂S/SO₂ via unique anionic redox pathways; (2) gas crosstalk between components creates compounding risks—retained gases induce electrolyte dry-out and ion transport barriers during cycling, while combustible gas–O₂ mixtures accelerate thermal runaway through chain reactions. This review proposes three key strategies to suppress gas generation: (1) oxygen lattice stabilization via dopant engineering, (2) solvent decomposition mitigation through tailored interphases engineering, and (3) gas-selective adaptive separator development. Furthermore, it establishes a multiscale design framework spanning atomic defect control to pack-level thermal management, providing actionable guidelines for battery engineering. By correlating early gas detection metrics with degradation patterns, the work enables predictive safety systems and standardized protocols, directly guiding the development of reliable high-energy batteries for electric vehicles and grid storage.

Correction for ‘Sodium cluster-driven safety concerns of sodium-ion batteries’ by Jiaping Niu et al., Energy Environ. Sci., 2025, 18, 2474–2484, https://doi.org/10.1039/D4EE05509H.