Yue-Peng Cai

Aqueous zinc-ion batteries (AZIBs) are promising next-generation energy storage devices but suffer from severe dendrite growth, primarily due to uncontrolled two-dimensional (2D) diffusion of Zn2+ and sluggish desolvation kinetics, which result in short cycle life under high-rate conditions. Here, we report tris(hydroxymethyl)aminomethane (Tham) as a novel electrolyte additive that simultaneously optimizes Zn2+ diffusion and accelerates desolvation. Tham preferentially adsorbs onto the zinc surface, forming a dense protective layer that compresses the electric double layer (EDL) (d2 < d1) and reconstructs the inner/outer Helmholtz planes (IHP/OHP). This adsorption reduces repulsive forces between Zn2+ ions, promotes three-dimensional (3D) diffusion, and enables uniform Zn deposition. Concurrently, Tham decreases the water coordination number in the Zn2+ solvation sheath from 5.28 to 4.81, modulates the lowest unoccupied molecular orbital (LUMO) energy, lowers the desolvation energy barrier, and effectively suppresses the hydrogen evolution reaction (HER). As a result, Zn||Zn symmetric cells achieve stable cycling for 2800 h at 1 mA cm–2 with an areal capacity of 1 mAh cm–2, Zn||Cu asymmetric cells deliver an average Coulombic efficiency of 99.83%, and Zn||NH4V4O10 full cells retain 92% of their initial capacity after 500 cycles at 1 A g–1. This straightforward strategy of EDL regulation combined with solvation sheath reconstruction significantly enhances the overall performance of AZIBs.

Lithium–metal batteries (LMBs) hold great promise for high-energy-density energy storage yet suffer from low Li plating/stripping Coulombic efficiency (CE), which originates from persistent electrolyte decomposition at the electrolyte/anode interface. Such parasitic reactions are driven by interfacial electron transfer, closely tied to both the passivation capability of solid electrolyte interphase (SEI) and reductive stability of electrolytes. Herein, the interfacial energy gap (ΔEgap) between Fermi level of Li/SEI and lowest unoccupied molecular orbital level of electrolyte is proposed as a descriptor to quantify the driving force for interfacial electron transfer, demonstrating that a reduced ΔEgap could effectively suppress interfacial parasitic reaction and thus enhance Li CE. Machine learning modeling coupled with Shapley additive analysis identifies the solvent minimum electrostatic potential (ESPmin) as the dominant governing factor of ΔEgap. Guided by these insights, we design two out-of-sample solvents with small ΔEgap, achieving high CEs exceeding 99%. Combined experimental and simulation results elucidate an ESPmin-governed interfacial regulation mechanism. This work provides a quantitative and interpretable strategy for rational electrolyte design toward highly reversible LMBs.

Stable cycling of Ni-rich positive electrodes under high voltages (≥ 4.6 V) is critically challenging due to severe interfacial parasitic reactions and structural degradation, especially under all-climate conditions (i.e., ≤ −20 °C and ≥ 55 °C). Herein, we rationally design and synthesize an asymmetric fluorinated sulfonamide solvent, N-ethyl-N-methyltrifluoromethane-sulfonamide, where the fluorination of sulfone backbone greatly promotes the oxidation stability, while the introduction of asymmetric amine group bestows the solvent with an low freezing point (below −150 °C). This obtained solvent, with 1 M lithium bis(fluorosulfonyl)imide, delivers high oxidation stability (above 5.0 V) and good Li reversibility (up to 99.8% in Li | |Cu cells). Coupled with its ability to form highly robust LiF-rich solid-electrolyte/cathode-electrolyte interphases, this single-salt single-solvent electrolyte enables stable cycling of Li | |Ni_0.8Co_0.1Mn_0.1 cells under an high voltage of 4.8 V across an wide temperature of −60 to 100 °C. Remarkably, a prototype 5 Ah-level Li | | Ni_0.8Co_0.1Mn_0.1 pouch cell at an cut-off voltage of 4.7 V and 0.1 C demonstrates a high specific energy (based on the mass of all components) of 514 Wh kg⁻¹ over 20 cycles.

Weakening the solvation ability has shown great potential in electrolyte solvent design to promote the cycling performance of Li-metal batteries, yet suffers from sluggish kinetics and uncontrolled Li dendrite formation, particularly at low temperatures. Herein, we propose a guideline for rational electrolyte solvent screening, where the restrained electrostatic potential of the coordinated O is proposed as one descriptor to quantify the solvation effect, followed by introducing the dipole moment as a correction descriptor to optimize solvents’ sensitivity to the electric fields and interphase stability. Under the guidance of this screening principle, a class of asymmetric fluorinated ethers is rationally designed, of which the 3,3,3-trifluoropropyl-1-methyl ether with moderate restrained electrostatic potential of the coordinated O and dipole moment is identified to mediate a stable six-membered chelating structure with Li⁺, significantly promoting Li kinetics and reversibility from 30 to −60 °C. Coupled with its good anodic stability, this single-salt single-solvent electrolyte enables the 50 μm Li | |4.0 mAh cm⁻² LiNi_0.8Mn_0.1Co_0.1O₂ coin-cells maintaining > 90% capacity after 200 cycles at benign and low temperatures. A practical Li-metal pouch-cell delivers a high specific energy (based on the mass of all components) of 345.3 Wh kg⁻¹ over 40 cycles at −40 °C.

Organic spacer cations critically influence the dimensionality and stability of low-dimensional perovskites (LDPs), yet current A-site candidate selection remains largely empirical. Herein, we present a machine-learning-driven molecular generation framework based on a Long Short-Term Memory Network model guided by key molecular descriptors, incorporating a Double-Fit strategy to improve dimensional property alignment and structural rationality of LDPs. Our model inversely generates organic cations targeting specific structural dimensions. Subsequent density functional theory calculations identify candidates with favorable thermodynamic stability and configurational features. Experimental synthesis and structural characterization of the resulting perovskites confirm the model's predictive accuracy. This approach provides a rational design paradigm for A-site cations in LDPs and establishes a general platform to accelerate discovery of new organic-inorganic hybrid perovskite materials.