Feng Pan

Amorphous solid electrolytes provide a promising route to overcoming the ion-transport limitations of crystalline halide frameworks, yet achieving superionic Na+ conduction remains challenging. Herein, we report a mixed-anion amorphous Na-ion solid-state electrolyte, TaCl5-0.5Na2S (NTSC), synthesized via high-energy ball-milling, which exhibits an ultrahigh room-temperature ionic conductivity of 2.9 mS/cm and a low activation energy of 0.276 eV. Structural analyses reveal a highly disordered framework composed of Ta-centered bipolyhedra interconnected via corner-sharing sulfur atoms [Ta2Cl10S], [TaCl5S], [TaCl4S], and [TaCl4S2], evidenced by comprehensive characterizations, forming a flexible, disordered amorphous network. Ab initio molecular dynamics (AIMD) simulations identify continuous Na+-diffusion pathways with low migration barriers. Complementary topological analyses further indicate that sulfur incorporation leads to local lattice distortions, shortens Na–Na hopping distances, and enhances framework flexibility, collectively enabling fast, multidimensional Na+ transport. When applied in all-solid-state sodium-ion batteries (ASSNIBs), NTSC enables high reversible capacity (111.95 mAh/g with a Coulombic efficiency of 92.6% at 0.1 C) and excellent cycling stability (76.9% initial capacity retention after 200 cycles at 0.2 C) at room temperature. This work establishes mixed-anion amorphization as an effective design strategy for high-performance Na-ion solid electrolytes.

The practical deployment of high‐voltage (≥4.5 V) LiCoO ₂ (LCO) cathodes under elevated temperatures is essential for meeting the growing energy‐storage demands across diverse applications. However, it is severely hindered by interfacial parasitic reactions arising from irreversible electron transfer between electrolyte solvents and the cathode. Herein, we demonstrate the regulation of the spatial distance and orientation of phosphate solvent molecules within the electric double layer at the LCO interface, thereby fundamentally suppressing irreversible interfacial spatial electron transfer (ISET) under combined high‐voltage and high‐temperature conditions. The fluorinated bidentate phosphate ester (TEFP) creates a compact solvation sheath that counteracts the interfacial‐electric‐field‐driven enrichment of phosphate solvents, increases the solvent‐cathode distance, and maintains a P═O orientation away from the cathode, thereby suppressing ISET from the P═O bond to the delithiated LCO. This simultaneously promotes the formation of a well‐controlled, uniform, and stable cathode–electrolyte interphase. Consequently, Li||LCO cells with TEFP electrolyte deliver superior cycling stability at 4.6 V and elevated temperatures, with 80% capacity retention after 760 cycles at 60°C and 75.5% after 300 cycles at 80°C, while Ah‐level pouch cells further validate the practical viability of the electrolyte. This work provides guidance for the design of cathode interfaces under high‐voltage and high‐temperature conditions.

The practical deployment of high‐voltage (≥4.5 V) LiCoO ₂ (LCO) cathodes under elevated temperatures is essential for meeting the growing energy‐storage demands across diverse applications. However, it is severely hindered by interfacial parasitic reactions arising from irreversible electron transfer between electrolyte solvents and the cathode. Herein, we demonstrate the regulation of the spatial distance and orientation of phosphate solvent molecules within the electric double layer at the LCO interface, thereby fundamentally suppressing irreversible interfacial spatial electron transfer (ISET) under combined high‐voltage and high‐temperature conditions. The fluorinated bidentate phosphate ester (TEFP) creates a compact solvation sheath that counteracts the interfacial‐electric‐field‐driven enrichment of phosphate solvents, increases the solvent‐cathode distance, and maintains a P═O orientation away from the cathode, thereby suppressing ISET from the P═O bond to the delithiated LCO. This simultaneously promotes the formation of a well‐controlled, uniform, and stable cathode–electrolyte interphase. Consequently, Li||LCO cells with TEFP electrolyte deliver superior cycling stability at 4.6 V and elevated temperatures, with 80% capacity retention after 760 cycles at 60°C and 75.5% after 300 cycles at 80°C, while Ah‐level pouch cells further validate the practical viability of the electrolyte. This work provides guidance for the design of cathode interfaces under high‐voltage and high‐temperature conditions.

Fluorinating electrolyte solvents is an effective strategy to enhance the interfacial stability of lithium‐ion batteries (LIBs) under high‐voltage conditions, where severe interfacial side reactions typically undermine the long‐term performance. However, the influence of both the number and positional arrangement of fluorinated groups on solvation structure remains poorly understood. In this work, we systematically investigate how trifluoromethyl group number and substitution position in diethyl carbonate (DEC) derivatives affect Li ⁺ solvation behavior. It is revealed that the introduction of a DEC‐based solvent with symmetric two trifluoromethyl groups tends to regulate the solvation structure enriched with anions and fluoroethylene carbonate (FEC). This optimized solvation structure facilitates the formation of a robust cathode‐electrolyte interphase derived from both anions and FEC. Consequently, Ni‐rich LiNi _0.8 Co _0.1 Mn _0.1 O ₂ cathodes with a high loading mass of 10.5 mg cm ⁻² achieve stable cycling at 4.6 V, retaining 80% of their capacity after 300 cycles. These findings provide fresh insights into the rational design of fluorinated solvents for high‐voltage LIBs.

Sodium‐ion batteries are considered strong contenders for high‐rate and high‐power energy storage owing to their favorable ion‐transport kinetics. However, under rapid Na ⁺ (de)intercalation, layered oxide cathodes are prone to highly non‐uniform Na ⁺ extraction, which readily induces pronounced lattice strain accumulation, triggering heterogeneous phase evolution, crack formation, and progressive structural degradation, ultimately limiting rate capability and cycling stability. Despite extensive efforts devoted to compositional optimization and surface modification, an intrinsic and structure‐level strategy for directly regulating rate‐dependent strain evolution in layered oxide cathodes remains elusive. Here, by introducing a coherently intergrown perovskite Ca ₂ MnO ₄ phase into a layered NaNi _1/3 Fe _1/3 Mn _1/3 O ₂ framework, a strain‐tolerant composite architecture is rationally constructed. The embedded perovskite phase effectively buffers lattice deformation and constrains strain accumulation during rapid Na ⁺ deintercalation, thereby stabilizing the structural evolution of the layered host. This strain‐buffering design concept provides new insights into lattice‐level regulation in layered oxide cathodes and opens a viable pathway toward the development of high‐rate and long‐life sodium‐ion batteries.

Nickel‐based layered cathodes are promising candidates for high‐performance, high‐energy lithium‐ion batteries, yet their high‐voltage application is jointly limited by synthesis‐inherited structural defects and an unstable lattice oxygen framework. Here, we show that both limitations can be overcome by decoupled synthesis pathway (DSP) via La/Nb oxalate functionalization of the Ni _0.6 Co _0.1 Mn _0.3 (OH) ₂ precursor. Unlike the conventional coupled synthesis pathway (CSP) where precursor dehydration and Li ₂ CO ₃ decomposition overlap in temperature, the DSP introduces a low‑temperature decomposition of La/Nb oxalates at 200°C, which effectively avoids localized contact between the precursor and Li ₂ CO ₃ and shifts Li ₂ CO ₃ ‐related reactions to high temperatures. This allows sequential precursor dehydroxylation, rock‑salt (RS) intermediate formation, and layered‑phase transformation over a broad temperature window. The resulting LiNi _0.6 Co _0.1 Mn _0.3 O ₂ cathode with La/Nb functionalization (NCM‐LN) features a uniform surface LaNiO ₃ perovskite heterostructure and a Nb‑doped layered bulk with suppressed RS and spinel defects. Consequently, under 4.5 V operation (vs. Li ⁺ /Li), NCM‐LN exhibits homogeneous Li ⁺ (de)intercalation, and a stabilized oxygen framework. In graphite||NCM‐LN full cells, NCM‐LN retains 80.1% of its capacity after 2000 cycles at 1C, substantially outperforming the pristine cathode. This decoupling strategy is broadly effective across various Ni‑based systems, providing a generalizable route toward high‑energy, long‑life cathode materials.

Constructing a robust solid electrolyte interphase (SEI) is a proven strategy to enhance the performance of Si‐based anodes by accommodating severe volume swings and suppressing interfacial side reactions. However, existing strategies that rely solely on either chemical coating or electrochemical formation struggle to reconcile SEI uniformity and long‐term stability. Here, we propose a synergistic strategy that integrates the interfacial modification with in situ regulated electrolyte decomposition. A conformal layer composed of LiF and Li ₃ PO ₄ is pre‐formed on SiO _x anodes, where LiF serves as a stable mechanical framework for the inorganic‐rich SEI, and Li ₃ PO ₄ selectively adsorbs fluoroethylene carbonate (FEC), favoring the polymerization of FEC‐derived species via interfacial enrichment to form the high‐molecular‐weight organic species. These electrochemically generated SEI components effectively compensate for the damage to the initial coating caused by volume expansion, enabling the SEI to possess both structural integrity and resilience. Consequently, the modified SiO _x anode exhibits benchmark electrochemical performance, delivering excellent cycling stability (1086 mA h g ⁻¹ , 81% capacity retention for 300 cycles at 0.8 A g ⁻¹ ) and high‐rate capability (1010 mAh g ⁻¹ at 2.4 A g ⁻¹ ). This work establishes a precedent for the dynamic repair interphase design paradigm for high‐capacity anodes.

Achieving a high plateau capacity in hard carbon (HC) anodes is one of the most critical prerequisites for high‐energy‐density sodium–ion batteries (SIBs), yet it is fundamentally limited by inaccessible closed pores formed during conventional high‐temperature annealing. Here, we propose a potentially scalable oxidation‐reconfiguration strategy to unlock its latent capacity. By coupling controlled oxidative etching with subsequent thermal reconstruction, an interconnected closed‐pore network is constructed. Oxidative pretreatment opens blocked channels and interconnects isolated voids, while reconstruction promotes void fusion, generating accessible internal reservoirs for the nucleation and storage of quasi‐metallic sodium clusters. This structural evolution and storage mechanism are elucidated by total neutron scattering, SAXS, in situ techniques, and simulations. As a result, the optimized ICP‐HC anode delivers reversible capacity 437 mAh g ⁻¹ with an initial Coulombic efficiency of 91.5%. It achieves an initial discharge plateau capacity of 399 mAh g ⁻¹ with fast kinetics (300 mAh g ⁻¹ at 2C), overcoming the capacity‐rate trade‐off. Furthermore, an NVP//ICP‐HC full cell shows excellent rate capability (96 mAh g ⁻¹ at 5C) and stable cycling (95% retention over 200 cycles at 1C). This work provides a scalable strategy for advanced carbon anodes in high‐energy‐density SIBs.

A deep understanding of reactant adsorption behaviors is crucial for unraveling structure–activity relationships and identifying simple descriptors for the kinetics of multi‐electron redox reactions, such as the sulfur redox process in Li–S batteries (LSBs). Recently, the “10‐electron rule” for evaluating the adsorption strength of single atoms ( E _ads ) has been established for free‐atom‐like single‐atom alloys (SAAs). However, our density‐functional theory calculations show that this rule is unfeasible for single‐atom catalysts (SACs) with metal centers covalently coordinated by nonmetal atoms. Herein, we proposed a new 18‐electron rule for covalent SACs by establishing the quasi‐atom interaction model ( Q ‐AIM), which interprets the U‐type behavior of E _ads (S) dominated by antibonding‐orbital filling. Additional calculations demonstrate that E _ads (S) can serve as an efficient descriptor of the kinetics of sulfur redox involving multiatom polysulfides. Then, guided by the efficient predictor and Q ‐AIM, we employed machine learning to screen ∼800,000 candidate SACs. Ultimately, we obtained over 400 and 8000 promising SACs for sulfur evolution and sulfur reduction, respectively. Furthermore, E _ads (S) can be extended to predict the catalytic performance of SACs in Li/Na/K‐S/Se batteries. This work not only simplifies complex multi‐electron processes to single‐atom adsorption energy but also establishes a link between occupied electronic states and the catalytic performance of SACs.