All-solid-state lithium-sulfur batteries (ASSLSBs) can overcome polysulfide shuttle problem and offer an economic, high-energy-density solution for next-generation energy storage. However, its solid-phase reaction mechanism remains unclear due to complex multiphase evolution, which is difficult to analyze using existing operando methods. Here, we design an in-situ cell enabling real-time sulfur K-edge X-ray absorption spectroscopy under practical conditions. Meanwhile, to address the complexity in spectra analysis, we introduce a hybrid method combining principal component analysis and constrained optimization, allowing robust quantitative spectral deconvolution despite severe peak overlap. Our results reveal a two-step discharge pathway: sulfur directly reduces to Li2S2 and then to Li2S. Additionally, we found that a P2S5 additive can react in-situ with Li2S to form the solid electrolyte Li3PS4, enhancing ionic conduction and promoting more complete discharge. This work establishes a general framework for real-time analysis of multiphase evolution during an electrochemical process and elucidates sulfur redox mechanisms in ASSLSBs.

Sulfide-based all-solid-state lithium metal batteries (ASSLMBs) promise high energy density and enhanced safety, but their practical application is limited by low critical current density (CCD) and poor cycling stability due to lithium dendrite penetration. In this study, we systematically investigate how pressure-induced densification governs the morphological evolution and electrochemical performance of Li5.5PS4.5Cl1.5 (LPSC) solid electrolytes. By varying the fabrication pressure from hundreds of MPa up to 1.5 GPa, we reveal the LPSC undergoes a distinct three-stage morphological evolution-from initially discrete particles, to plastic-deformation-assisted pressure sintering, and ultimately to the formation of locally-oriented flake-like microstructures. This progressive densification substantially decreases the subsurface pore volume, and eliminates interconnected percolating pores. Under 1.5 GPa, ultra-densified LPSC pellets are obtained with relative density > 99%. The highly optimized microstructure of ultra-densified LPSC leads to outstanding electrochemical performance: a record-high CCD of 10 mA cm(-2), stable long-term cycling of Li symmetric cells for over 2250 h at 3 mA cm(-2), and durable long-cycling of Li//S full cells for over 350 cycles at 3 mA cm(-2), with a capacity retention of 85.5%. These results highlight that ultra-densification of sulfide solid electrolytes plays a decisive role in suppressing lithium dendrites, and ensuring long-term stability of ASSLMBs.

Lithium dendrite penetration through solid electrolyte has been the major obstacle for practical sulfide-based all-solid-state lithium metal batteries (ASSLMBs). Herein, a series of tailored model solid cells are designed to investigate the intrinsic lithium growth behavior at open surfaces and internal cracks of sulfide solid electrolyte. It is shown that when plating lithium on the open surface of electrolyte (free space), the lithium exhibits an intrinsic columnar growth behavior perpendicular to the electrolyte surface, preferentially along the (110) crystal axis. When plating lithium within the internal cracks (confined free space), the growth of lithium follows two major modes: 1) Diffusion creep enabled infiltration along the crack side-wall surface toward the counter electrode, allowing the deposited lithium to cause short circuit without fully filling the crack; 2) Columnar growth perpendicular to the crack side-wall surface toward the confined free space inside the crack. The extent of lithium ingress into electrolyte under external pressure in the initial state is found to determine the rate of lithium infiltration after applying the current. As a further validation, intact sintered electrolytes with 99% relative density minimize initial lithium ingress, enabling lithium plating at 6.37 mA cm-2 with an areal capacity exceeding 76 mAh cm-2 without short circuit.

Magnesium–sulfur (Mg–S) batteries are promising candidates for high‐energy‐density storage systems, but their performance is critically dependent on the interfacial properties of both the anode and cathode. This study explores a dual‐interface regulation strategy to enhance Mg–S battery performance via tailored electrolyte additives. For the anode, tetrabutylammonium bromide (TBABr) is added to commercially available chlorine‐free Mg(TFSI) 2 ‐based electrolytes, forming a robust bromide‐containing solid electrolyte interphase (SEI) that extend the cycle life of Mg//Mg cells. For the cathode, 1,3,5‐benzenetrithiol (BTT) is introduced as a cathode‐electrolyte interface (CEI) modifier to promote the formation of an organopolysulfide interfacial layer that effectively mitigates polysulfide shuttling. This dual‐interface regulation approach greatly increase the cycle lives of the Mg–S cells and the magnesium–selenium (Mg–Se) cells. This work underscores the importance of a holistic interfacial engineering strategy and provides valuable insights for the development of high‐performance Mg–S batteries.

All‐solid‐state lithium–sulfur batteries (ASSLSBs) are promising for next‐generation energy storage. However, the limited ionic and electronic conductivities of sulfur‐based cathodes make them difficult to realize high sulfur content and high areal loading. Herein, a facile approach of in situ solid electrolyte formation is used to build ionic pathways in high sulfur loading cathodes. A precursor of P₂S₅ is introduced into the interior space of sulfur‐carbon secondary particles, and its in situ reaction with the discharge product Li₂S forms lithium phosphorus sulfide solid‐state electrolyte that establishes 3D ionic pathways within the cathodes. This approach not only activates more active materials but also boosts the overall ionic conductivity of the cathodes. The optimized cathode with a sulfur loading of 4 mg cm −2 can achieve a high specific capacity of 1340 mAh g −1 (based on sulfur mass) with 89% capacity retention after 100 cycles at 0.1C (1C = 1675 mA g −1 ). Even with a higher sulfur loading of 8 mg cm −2 , the cathode still demonstrates a very high active materials utilization with an areal capacity of 9.2 mAh cm −2 . The simple and effective method to realize high‐performance sulfur cathode with built‐in solid electrolyte ionic pathways would be useful for the further development of practical ASSLSBs.

Rechargeable magnesium metal batteries need an electrolyte that forms a stable and ionically conductive solid electrolyte interphase (SEI) on the anodes. Here, we used molecular dynamic simulation, density functional theory calculation, and X‐ray photoelectron spectroscopy analysis to investigate the solvation structures and SEI compositions in electrolytes consisting of dual‐salts, magnesium bis(trifluoromethanesulfonyl)imide (MgTFSI 2 ), and MgCl 2 , with different additives in 1,2‐dimethoxyethane (DME) solvent. We found that the formed [Mg 3 (μ‐Cl) 4 (DME) m TFSI 2 ] ( m = 3, 5) inner‐shell solvation clusters in MgTFSI 2 ‐MgCl 2 /DME electrolyte could easily decompose and form a MgO‐ and MgF 2 ‐rich SEI. Such electron‐rich inorganic species in the SEI, especially MgF 2 , turned out to be detrimental for Mg plating/stripping. To reduce the MgF 2 and MgO contents in SEI, we introduce an electron‐deficient tri(2,2,2‐trifluoroethyl) borate (TFEB) additive in the electrolyte. Mg//Mg cells using the MgTFSI 2 ‐MgCl 2 /DME‐TFEB electrolyte could cycle stably for over 400 h with a small polarization voltage of ~150 mV. Even with the presence of 800 ppm H 2 O, the electrolyte with TFEB additive could still preserve its good electrochemical performance. The optimized electrolyte also enabled stable cycling and high‐rate capability for Mg//Mo 6 S 8 and Mg//CuS full cells, showing great potential for future applications.

Dendrite growth behavior in a thin lithium phosphorus sulfide (LPSC) solid electrolyte has not been well revealed due to the lack of a suitable characterization method. This work introduces a unique yet simple method to monitor dendrite growth inside a pressurized all-solid-state cell in real time. Once a lithium metal dendrite penetrates through a thin LPSC layer and enters a LPSC-PTFE (polytetrafluoroethylene) indicator layer, it will react with PTFE and form a black-colored electron-conductive substance that traces the dendrite growth pathways, which can be in situ or ex situ observed using an optical microscope. It is shown that dendrites tend to grow through a very thin LPSC layer even at a very low current density, probably along the pre-existing chains of defects, revealing a potential challenge for practical application of all-solid-state lithium metal batteries. To address this challenge, we added an appropriate amount of LiF in LPSC electrolyte to increase its interface energy with lithium and effectively inhibit dendrite growth. Using the LPSC-LiF composite electrolyte, a Li|Li symmetric cell can achieve 1800 h ultralong cycling life at a current density of 0.5 mA cm-2 and an all-solid-state Li|LPSC-LiF|LiCoO2 full cell can operate over 200 cycles without short-circuiting, showing great promise for its application in future all-solid-state lithium metal batteries.

Si has been regarded as a highly promising material for thin-film lithium-ion battery (LIB) anode due to its high capacity and compatibility. However, the practical application of Si anode remains challenging owing to the binder-free and conductive additive-free environment of thin film battery, which leads to issues such as poor electrical conductivity and mechanical instability. This study proposes a viable solution to improve the cycling stability by adopting a combined high-entropy and amorphization strategy. The high-entropy amorphous thin films (HEATFs) comprising lithium-reactive elements, Si, Al, Mg, Ge, Sn, and Zn, demonstrate a high capacity of 2200 mAh/g and a capacity retention of 94.6 % after 50 cycles. In contrast, Si thin film anodes experience a rapid capacity decline, with only 14.3 % capacity retention after 20 cycles. By employing in-situ transmission electron microscopy and X-ray photoemission spectroscopy, we uncover that the improved structural stability arises from a solid-solution reaction mechanism with restricted phase separation of Si, Al, Mg, and Ge, which relieves internal stress and maintains structural integrity. Additionally, the formation of Sn nanocrystals embedded within the amorphous matrix enhances Li+ transport kinetics. These findings highlight the significance of structural and compositional complexity of Si-based high-entropy materials for their electrochemical performance improvement, presenting a new design concept for high-energy-density thin-film LIB anodes.

Alloying-type anode materials provide high capacity for lithium-ion batteries; however, they suffer pulverization problems resulting from the volume change during cycling. Realizing the cycling reversibility of these anodes is therefore critical for sustaining their electrochemical performance. Here, we investigate the structural reversibility of Sn NPs during cycling at atomic-level resolution utilizing in situ high-resolution TEM. We observed a surprisingly near-perfect structural reversibility after a complete cycle. A three-step phase transition happens during lithiation, accompanied by the generation of a significant number of defects, grain boundaries, and up to 202% volume expansion. In subsequent delithiation, the volume, morphology, and crystallinity of the Sn NPs were restored to their initial state. Theoretical calculations show that compressive stress drives the removal of vacancies generated within the NPs during delithiation, therefore maintaining their intact morphology. This work demonstrates that removing vacancies during cycling can efficiently improve the structural reversibility of high-capacity anode materials.

Two-dimensional (2D) semiconductors are promising in channel length scaling of field-effect transistors (FETs) due to their excellent gate electrostatics. However, scaling of their contact length still remains a significant challenge because of the sharply raised contact resistance and the deteriorated metal conductivity at nanoscale. Here, we construct a 1D semimetal-2D semiconductor contact by employing single-walled carbon nanotube electrodes, which can push the contact length into the sub-2 nm region. Such 1D-2D heterostructures exhibit smaller van der Waals gaps than the 2D-2D ones, while the Schottky barrier height can be effectively tuned via gate potential to achieve Ohmic contact. We propose a longitudinal transmission line model for analyzing the potential and current distribution of devices in short contact limit, and use it to extract the 1D-2D contact resistivity which is as low as 10-6 Ω·cm2 for the ultra-short contacts. We further demonstrate that the semimetal nanotubes with gate-tunable work function could form good contacts to various 2D semiconductors including MoS2, WS2 and WSe2. The study on 1D semimetal contact provides a basis for further miniaturization of nanoelectronics in the future.

High-performance magnesium electrolyte is crucial for the practical application of rechargeable Mg batteries. Herein, a bis(2,2,2-trifluoroethyl) ether (BTFE) cosolvent is introduced into the chlorine-containing Mg electrolytes. Theoretical calculations and experimental characterizations reveal that the positive electrostatic potential distributed around the hydrogen atoms in a BTFE molecule could interact with Cl- and facilitate the formation of charged, instead of neutral, ion-solvent clusters in the BTFE cosolvated magnesium lithium chloride complex (MLCC) electrolyte, which helps to lift its ionic conductivity. The modified solvation structure also lowers the lowest unoccupied molecular orbital energy level of the ion-solvent clusters, facilitating the in situ formation of solid electrolyte interphase. Using the BTFE cosolvated MLCC electrolyte, reversible Mg plating/stripping can be achieved at 20 mA cm(-2) in a Mg//Mg cell, and an ultra-long cycle life of 1200 h can be achieved at 5 mA cm(-2). The new electrolyte also enables high capacity retention of 160 mAh g(-1) after 800 cycles for a Mg//CuS full cell, or super-long cycle life of over 10 000 cycles at 80 C for a Mg//Mo6S8 full cell. The merits of BTFE cosolvent, universally applicable to other chlorine-containing Mg electrolytes, open a way to develop practical Mg battery electrolytes.

A dendrite-free lithium metal anode requires a stable interface designed for efficient and reversible lithium plating and stripping. In this work, we have devised a mechanically flexible artificial Li3N solid-electrolyte interlayer supported by a dual-layer compactness-tailored carbon nanotube fiber network. The more compact side of the network ensures a full coverage of Li3N, which prevents the reaction between electrolyte and lithium. The other side, with sparsely distributed nanotube fibers, provides mechanical flexibility for the film, and induces three-dimensional lithium deposition along its structure without any dendrite formation. The resulting full cell with NCM811 cathode has a high capacity retention of 95.1% for 160 cycles compared with less than 80% for the control.

•LiHMDS with water-resistant capability is found to assist the solvation of MgCl2 in THF solvent by ion association.•A small amount of LiHMDS in MgCl2/THF contributes to reduce the de-solvation energy of Mg2+by forming [MgxLiyHMDSzCl2x+y-z· nTHF] aggregates.•An increasing amount of LiHMDS in MgCl2/THF makes the functional [MgxLiyHMDSzCl2x+y-z· nTHF] start to dissociate.•LiCl as co-additive can avoid the dissociation of [MgxLiyHMDSzCl2x+y-z· nTHF].•A Mg//Mo6S8 full cell can be cycled for over 10,000 cycles with a superior capacity retention of 83 mA h g–1 even under an ultrahigh rate of 31.1 C (1 C = 128.8 mA g–1).

Passivation of the Mg anode surface in conventional electrolytes constitutes a critical issue for practical Mg batteries. In this work, a perfluorinated tert-butoxide magnesium salt, Mg(pftb)2 , is codissolved with MgCl2 in tetrahydrofuran (THF) to form an all-magnesium salt electrolyte. Raman spectroscopy and density function theory calculation confirm that [Mg2 Cl3 ·6THF]+ [Mg(pftb)3 ]- is the main electrochemically active species of the electrolyte. The proper lowest unoccupied molecular orbital energy level of the [Mg(pftb)3 ]- anion enables in situ formation of a stable solid electrolyte interphase (SEI) on Mg anodes. A detailed analysis of the SEI reveals that its stability originates from a dual-layered organic/inorganic hybrid structure. Mg//Cu and Mg//Mg cells using the electrolyte achieve a high Coulombic efficiency of 99.7% over 3000 cycles, and low overpotentials over ultralong-cycle lives of 8100, 3000, and 1500 h at current densities of 0.5, 1.0, and 2.0 mA cm-2 , respectively. The robust SEI layer, once formed on a Mg electrode, is also shown highly effective in suppressing side-reactions in a TFSI- -containing electrolyte. A high Coulombic efficiency of 99.5% over 800 cycles is also demonstrated for a Mg//Mo6 S8 full cell, showing great promise of the SEI forming electrolyte in future Mg batteries.

Although employing solid polymer electrolyte (SPE) in all-solid-state lithium/sulfur (ASSLS) batteries is a promising approach to obtain a power source with both high energy density and safety, the actual performance of SPE-ASSLS batteries still lag behind conventional lithium/sulfur batteries with liquid ether electrolyte. In this work, combining characterization methods of X-ray photoelectron spectroscopy, in situ optical microscopy, and three-electrode measurement, a direct comparison between these two battery systems is made to reveal the mechanism behind their performance differences. In addition to polysulfides, it is found that the initial elemental sulfur can also dissolve into and diffuse through the SPE to reach the anode. Different from the shuttle effect that causes uniform corrosion on the anode in a liquid electrolyte, dissolved sulfur species in SPE unevenly passivate the anode surface and lead to the inhomogeneous Li+ plating/stripping at the anode/SPE solid-solid interface. Such inhomogeneity eventually causes void formation at the interface, which leads to the failure of SPE-ASSLS batteries. Based on this understanding, a protection interlayer is designed to inhibit the shuttling of sulfur species, and the modified SPE-ASSLS batteries show much-improved performance in cycle life.

The revival of lithium metal anodes (LMAs) makes it a potent influence on the battery research community in the recent years after the popularity of Li-ion batteries with graphite anodes. The main reason is due to the over ten-fold increase in the capacity of LMAs when compared with that obtained when using graphite, as well as the low redox potential of Li/Li+. However, the full potential of LMAs is heavily inhibited by several factors, such as dendrite growth, pulverization, side reactions, and volume changes. These adversities lower the cell's Coulombic efficiency dramatically if operated without massively excessive Li usage. In this review, we first introduce some of the most significant progresses made in the understandings of the charging/discharging processes at the anode. The importance of combining advanced characterization techniques with classical methods is highlighted. In particular, we aim to explore the hidden links between those studies for obtaining deeper insights. Two main categories of solutions to address common problems, namely, lithium-electrolyte interfacial engineering and three-dimensional hosting of Li, are subsequently illustrated, where each subsection takes a different methodological perspective to demonstrate the relevant state-of-the-art studies. Some interesting approaches to stop dendrites and a brief note on the practical aspects of lithium-metal batteries are provided, too. This review concludes with our essential discoveries from the current literature and valuable suggestions for future LMA research.

Rational design of a robust carbon matrix has a profound impact on the performance of flexible/wearable lithium/sulfur batteries. Herein, we demonstrate a freestanding three-dimensional super-aligned carbon nanotube (SACNT) matrix reinforced with a multi-functionalized carbon coating for flexible, high-areal sulfur loading cathode. By employing the sulfur/nitrogen co-doped carbon (SNC) “glue”, the joints in the SACNT scaffold are tightly welded together so that the overall mechanical strength of the electrode is significantly enhanced to withstand the repeated bending as well as the volume change during operation. The SNC also shows intriguing catalytic effect that lowers the energy barrier of Li ion transport, propelling a superior redox conversion efficiency. The resulting binder-free and current collector-free sulfur cathode exhibits a high reversible capacity of 1,079 mAh·g−1 at 1 C, a high-rate capacity of ∼ 800 mAh·g−1 at 5 C, and an average capacity decay rate of 0.037% per cycle at 2 C for 1,500 cycles. Impressively, a large-areal flexible Li/S pouch cell based on such mechanically robust cathode exhibits excellent capacity retention under arbitrary bending conditions. With a high areal sulfur loading of 7 mg·cm−2, the large-areal flexible cathode delivers an outstanding areal capacity of 6.3 mAh·cm−2 at 0.5 C (5.86 mA·cm−2), showing its promise for realizing practical high energy density flexible Li/S batteries.

Community structure is the basic structure of a social network. Nodes of a social network can naturally form communities. More specifically, nodes are densely connected with each other within the same community while sparsely between different communities. Community detection is an important task in understanding the features of networks and graph analysis. At present there exist many community detection methods which aim to reveal the latent community structure of a social network, such as graph-based methods and heuristic-information-based methods. However, the approaches based on graph theory are complex and with high computing expensive. In this paper, we extend the density concept and propose a density peaks based community detection method. This method firstly computes two metrics-the local density ρ and minimum climb distance δ -for each node in a network, then identify the nodes with both higher ρ and δ in local fields as each community center. Finally, rest nodes are assigned with corresponding community labels. The complete process of this method is simple but efficient. We test our approach on four classic baseline datasets. Experimental results demonstrate that the proposed method based on density peaks is more accurate and with low computational complexity.

Currently, dynamic causal modeling (DCM) is one of the most widely used models for an effective brain connectivity network, but it also has some disadvantages (e.g., researchers' selection of cerebral regions of interest [ROIs] is subjective, a substantial time is required for computation, etc.). Statistical Parametric Mapping (SPM) is the most popular statistical data analysis software for brain function, but its settings cumbersome, especially the data preprocessing section. In response to these disadvantages of DCM and SPM, we designed and created a computer-aided system for an effective brain connectivity network, modularized the data preprocessing section of SPM, and we explored the cerebral ROIs and possible co-activation network based on our proposed approach. The co-activation network has as a prior interconnection relationship, and it is used to assist in the selection of ROIs in similar cognitive experiments; thus, the testing of meaningless noise connection modes by the DCM is prevented, the number of models DMC is decreased, and the accuracy of the conclusions and computational efficiency of the DCM are improved.