Weijiang Xue

Micron‐sized silicon (µ‐Si) offers a scalable pathway to high‐capacity anodes, and its application in solid‐electrolyte‐free systems has garnered attention as a strategy to maximize energy density. However, achieving both high energy and power densities in such configurations remains challenging due to the lack of internal ionic conduction pathways and stress‐accommodation mechanisms. Here, we report a Chain‐based Networking (CN)‐Si electrode architecture that overcomes these limitations and maximizes energy and power densities without incorporating solid electrolytes within the electrode. In this design, µ‐Si particles are tightly wrapped and interconnected by single‐walled carbon nanotubes (CNTs), forming a mechanically robust conductive network. The CNT wrapping imposes compressive stress during lithiation, distributing internal strain and preventing crack and void formation, mimicking the stress‐dissipation principle of Prince Rupert's drop. As a result, the CN‐Si electrode delivers superior electrochemical performance, with 78% capacity retention at 3C, significantly outperforming conventional Si electrodes using polymer or carbon black binders. In full‐cell configurations with LiNi _0.8 Mn _0.1 Co _0.1 O ₂ (NCM811) cathodes, the CN‐Si electrode retains 78.8% capacity after 3000 cycles at a high C‐rate (5C). These findings demonstrate that stress‐engineered micro‐Si architectures can simultaneously overcome kinetic limitations and maximize both energy and power densities in solid‐state battery systems, advancing practical high‐performance All‐Solid‐State Batteries (ASSBs).

Simultaneously achieving stable lithium metal batteries (LMBs) under cryogenic and high‐voltage conditions remains a fundamental challenge due to uncontrolled interfacial chemistry at lithium anodes and nickel‐rich cathodes. Here, we report an intramolecular polarization strategy that jointly regulates Li ⁺ solvation dynamics, solid electrolyte interphase (SEI) formation, and cathode electrolyte interphase (CEI) stress dissipation. An intramolecularly polarized electrolyte featuring orthogonally arranged electron donor–acceptor moieties with a dipole moment (∼4.2 D) establishes a potential–dependent solvation screening effect, reducing Li ⁺ desolvation energy to 38.1 kJ mol ⁻¹ , while enabling anodic stability beyond 5.3 V. The tailored solvation chemistry induces spontaneous formation of dual–gradient interphases composed of a LiF–rich SEI and a boroxane–incorporated CEI with an interface modulus ∼20 nN. Consequently, Li||Li symmetric cells exhibit stable cycling over 16 000 h with a minimal polarization of 8.3 mV. Full cells employing LiNi _0.8 Co _0.1 Mn _0.1 O ₂ cathodes retain 90% capacity after 1000 cycles at 4.5 V and maintain 80% at 4.9 V. 3 Ah pouch cells achieve a high energy density of 509 Wh kg ⁻¹ at 30°C with 96.8% capacity retention after 80 cycles, while delivering 439.1 Wh kg ⁻¹ at −30°C. This work establishes a molecular polarization paradigm for electrolyte and interphase engineering toward high–energy–density LMBs under extreme conditions.

P2-type layered transition metal oxides (NaxTMO2 TM are transition metal elements) are air-stability and low-cost but intrinsically limited in capacity, necessitating elevated charging voltages to unlock deeper Na+ extraction and higher energy density. However, practical high-voltage operation over wide temperature ranges is impeded by sluggish Na+ desolvation, aggravated parasitic reactions, and rapid cycling degradation. Here, we identify 1,1,1-trifluoro-N,N-dimethylmethanesulfonamide (Me2TFMSA) as a polar inducer that restructures Na+ solvation by confining carbonate molecules predominantly within the first solvation sheath, suppressing free-carbonate preferential accumulation at the cathode interface and enabling rapid ligand exchange during desolvation, while FSI– coordination forms an aggregate-rich solvation structure with weakened Na+–solvent interaction. This confining solvation electrolyte (CSE) allows a 4.3 V cutoff (vs 4.1 V conventionally) and delivers a 25.8% capacity gain for P2-type Na0.6[Mg0.04Ca0.02Ti0.1Mn0.55Ni0.29]O2 (NaNMO) cathodes, effectively suppressing parasitic reactions, transition-metal dissolution, surface phase reconstruction, and impedance growth. In 4.3-V-class Ah-level hard carbon||NaNMO pouch cells with the CSE deliver 74.8% capacity retention after 800 cycles at 0.5 C, whereas conventional carbonate electrolytes fail within 200 cycles. Stable performance is achieved from −30 to 45 °C, with good cycling performance at −20 °C. These results correlate solvation confinement with interfacial stability and 4.3-V-class pouch-cell performance in P2-type sodium-ion batteries.

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.

Amorphous–crystalline dual-phase grain structure often enables materials with unique performance. This is especially the case for the garnet-type solid-state electrolyte Li ₇ La ₃ Zr ₂ O ₁₂ (LLZO), which is a promising candidate for hybrid and all-solid-state lithium batteries. A major synthesis challenge, however, is that amorphous LLZO is difficult to retain via conventional sintering and even Flash Joule heating. Using electron beam focused to sub-millimeter scale with point-by-point scanning, we achieved highly localized heating to very high temperature followed by ultrafast quenching, enabling the direct fabrication of uniformly fine-grained amorphous–crystalline dual-phase LLZO. Fast ion transport offered by the crystalline grains, together with the amorphous shell that promotes a more homogeneous space-charge distribution at grain boundaries, markedly enhance the critical current density, cycling stability, and optical transparency. Our scalable fabrication route offers unparalleled tunability in electrochemical performance, and also has broad applicability for other functional ceramic systems requiring optimized electrical and optical properties.

Sodium‐ion batteries (SIBs) have emerged as one of the most promising candidates among post‐Li‐ion batteries (LIBs) due to abundance and low cost of sodium resources. However, the commercialization of SIBs is hindered by their limited cell performance. Although great efforts have been made, it is still challenging to balance the trade‐off between energy density and cycle life while simultaneously meeting the requirements for practical applications, which are largely governed by the stability of the electrode/electrolyte interfaces. Therefore, it is crucial to design new electrolyte components or formulations to stabilize the interphases and thus the cycling stability for high‐energy and high‐capacity cathodes/anodes. In this review, based on a comprehensive comparison of the fundamental mechanisms between SIBs and LIBs, the challenges and governing principles for electrolyte design in SIBs are first introduced. The progress in electrolyte designs for various high‐energy cathodes is summarized according to their ion‐transport characteristics and the interphase formation. Electrolyte design strategies, particularly for the high‐capacity anodes, are also surveyed, together with effective electrolyte design strategies to fulfill the requirements under practical operating conditions. Finally, future perspectives on electrolyte development from the viewpoints of full cell‐level performance, cost, and feasibility are highlighted. This review aims to provide a roadmap for advancing electrolyte design toward practical SIBs competitive with LIBs.

All-solid-state lithium batteries for electric vehicles require high specific power, challenged in thick negative electrodes by fragile conducting networks during volume changes and dendrite growth at high currents. We propose an In_0.38Sn_0.33Bi_0.29 ternary alloy negative electrode creating a mixed ionic-electronic conducting continuum that overcomes these limitations. The stepwise formation of multiple phases with sufficient mechanical robustness during Li-alloying effectively stabilizes the ionic and electronic conducting percolation by relieving stress concentration and minimizing crack propagation. The unique reversibility of the multiple phase changes during lithiation/delithiation ensures stable cycling performance. The In_0.38Sn_0.33Bi_0.29 negative electrode exhibits a high capacity of ~ 724 mAh g⁻¹ and a critical current density of 150 mA cm⁻² at 5.0 mAh cm^–2. The In_0.38Sn_0.33Bi_0.29 | |LiCoO₂ full cell with industry-level mass loading (6.49 mAh cm^–2) can retain 87.5% capacity over 1300 cycles at 4.0 C, delivering a jellyroll specific energy of 203.1 Wh kg⁻¹ and 670.6 Wh L⁻¹ at 5.0 C. The fast-charging capability is further validated by large-format pouch cells. The design principles can be extended to other negative electrode designs for solid-state batteries.