Degradation Evolution for Li2 ZrCl6 Electrolytes in Humid Air and Enhanced Air Stability via Effective Indium Substitution.

Superionic halides have aroused interests in field of solid electrolytes such as Li2 ZrCl6 . However, they are still facing challenges including poor air stability which lacks in-depth investigation. Here, moisture instability of Li2 ZrCl6 is demonstrated and decomposition mechanism in air is clearly revealed. Li2 ZrCl6 decomposes into Li2 ZrO3 , ZrOCl2 ·xH2 O and LiCl during initial stage as halides upon moisture exposure. Later, these side products evolve into LiCl(H2 O) and Li6 Zr2 O7 after longer time exposure. More importantly, structure of destroyed halides cannot be recovered after postheating. Later, Indium is doped into Li2 ZrCl6 (9.7 × 10-5 S cm-1 ) to explore its effect on structure and properties. Crystal structure of ball-milled In-doped Li2 ZrCl6 electrolytes is converted from the Li3 YCl6 -like to Li3 InCl6 -like with increasing In content and ionic conductivity can also be enhanced (0.768-1.13) × 10-3 S cm-1 ). More importantly, good air stability of optimal Li2.8 Zr0.2 In0.8 Cl6 is achieved since halide hydrates are formed after air exposure instead of total decomposition and the hydrates can be restored to Li2.8 Zr0.2 In0.8 Cl6 after postheating. Moreover, reheated Li2.8 Zr0.2 In0.8 Cl6 after air exposure is successfully applied in solid-state LiNi0.8 Co0.1 Mn0.1 O2 /halides/Li6 PS5 Cl/Li-In battery. The results in this work can provide insights into air instability of Li2 ZrCl6 and effective strategy to regulate air stability of halides.

An Advanced Gel Polymer Electrolyte for Solid-State Lithium Metal Batteries.

All-solid-state lithium metal batteries (LMBs) are regarded as one of the most viable energy storage devices and their comprehensive properties are mainly controlled by solid electrolytes and interface compatibility. This work proposes an advanced poly(vinylidene fluoride-hexafluoropropylene) based gel polymer electrolyte (AP-GPEs) via functional superposition strategy, which involves incorporating butyl acrylate and polyethylene glycol diacrylate as elastic optimization framework, triethyl phosphate and fluoroethylene carbonate as flameproof liquid plasticizers, and Li7La3Zr2O12 nanowires (LLZO-w) as ion-conductive fillers, endowing the designed AP-GPEs/LLZO-w membrane with high mechanical strength, excellent flexibility, low flammability, low activation energy (0.137 eV), and improved ionic conductivity (0.42 × 10-3 S cm-1 at 20 °C) due to continuous ionic transport pathways. Additionally, the AP-GPEs/LLZO-w membrane shows good safety and chemical/electrochemical compatibility with the lithium anode, owing to the synergistic effect of LLZO-w filler, flexible frameworks, and flame retardants. Consequently, the LiFePO4/Li batteries assembled with AP-GPEs/LLZO-w electrolyte exhibit enhanced cycling performance (87.3% capacity retention after 600 cycles at 1 C) and notable high-rate capacity (93.3 mAh g-1 at 5 C). This work proposes a novel functional superposition strategy for the synthesis of high-performance comprehensive GPEs for LMBs.

Ultrafast-Loaded Nickel Sulfide on Vertical Graphene Enabled by Joule Heating for Enhanced Lithium Metal Batteries.

The design and fabrication of a lithiophilic skeleton are highly important for constructing advanced Li metal anodes. In this work, a new lithiophilic skeleton is reported by planting metal sulfides (e.g., Ni3S2) on vertical graphene (VG) via a facile ultrafast Joule heating (UJH) method, which facilitates the homogeneous distribution of lithiophilic sites on carbon cloth (CC) supported VG substrate with firm bonding. Ni3S2 nanoparticles are homogeneously anchored on the optimized skeleton as CC/VG@Ni3S2, which ensures high conductivity and uniform deposition of Li metal with non-dendrites. By means of systematic electrochemical characterizations, the symmetric cells coupled with CC/VG@Ni3S2 deliver a steady long-term cycle within 14 mV overpotential for 1800 h (900 cycles) at 1 mA cm-2 and 1 mAh cm-2. Meanwhile, the designed CC/VG@Ni3S2-Li||LFP full cell shows notable electrochemical performance with a capacity retention of 92.44% at 0.5 C after 500 cycles and exceptional rate performance. This novel synthesis strategy for metal sulfides on hierarchical carbon-based materials sheds new light on the development of high-performance lithium metal batteries (LMBs).

Cubic Iodide Lix YI3+x Superionic Conductors through Defect Manipulation for All-Solid-State Li Batteries.

Halide solid electrolytes (SEs) have attracted significant attention due to their competitive ionic conductivity and good electrochemical stability. Among typical halide SEs (chlorides, bromides, and iodides), substantial efforts have been dedicated to chlorides or bromides, with iodide SEs receiving less attention. Nevertheless, compared with chlorides or bromides, iodides have both a softer Li sublattice and lower reduction limit, which enable iodides to possess potentially high ionic conductivity and intrinsic anti-reduction stability, respectively. Herein, we report a new series of iodide SEs: Lix YI3+x (x=2, 3, 4, or 9). Through synchrotron X-ray/neutron diffraction characterizations and theoretical calculations, we revealed that the Lix YI3+x SEs belong to the high-symmetry cubic structure, and can accommodate abundant vacancies. By manipulating the defects in the iodide structure, balanced Li-ion concentration and generated vacancies enables an optimized ionic conductivity of 1.04 × 10-3  S cm-1 at 25 °C for Li4 YI7 . Additionally, the promising Li-metal compatibility of Li4 YI7 is demonstrated via electrochemical characterizations (particularly all-solid-state Li-S batteries) combined with interface molecular dynamics simulations. Our study on iodide SEs provides deep insights into the relation between high-symmetry halide structures and ionic conduction, which can inspire future efforts to revitalize halide SEs.

Highly Stable Potassium Metal Anodes with Controllable Thickness and Area Capacity.

K metal battery is a kind of high-energy-density storage device with economic advantages. However, due to the dendrite growth and difficult processing characteristics, it is difficult to prepare stable K metal anode with thin thickness and fixed area capacity, which severely limits its development. In this work, a multi-functional 3D skeleton (rGCA) is synthesized by simple vacuum filtration and thermal reduction, and K metal anodes with controllable thickness and area capacity (K content) can be fabricated by changing the raw material mass and graphene layer spacing of rGCA. Moreover, the graphene sheet layer of rGCA can relax stress and relieve volume expansion; carbon nanotubes can serve as the fast transport channel of electrons, reducing internal impedance and local current density; Ag nanoparticles can induce the uniform nucleation and deposition of K+ . The K metal composite anodes (rGCA-K) based on the conductive skeleton can effectively suppress dendrites and exhibit excellent electrochemical performance in symmetric and full cells. The controllable fabrication process of stable K metal anode is expected to help K metal batteries move toward the stage of commercial production.

Solid-State Electrolytes in Lithium-Sulfur Batteries: Latest Progresses and Prospects.

Solid-state lithium-sulfur batteries (SSLSBs) have attracted tremendous research interest due to their large theoretical energy density and high safety, which are highly important indicators for the development of next-generation energy storage devices. Particularly, safety and "shuttle effect" issues originating from volatile and flammable liquid organic electrolytes can be fully mitigated by switching to a solid-state configuration. However, their road to thecommercial application is still plagued with numerous challenges, most notably the intrinsic electrochemical instability of solid-state electrolytes (SSEs) materials and their interfacial compatibility with electrodes and electrolytes. In this review, a critical discussion on the key issues and problems of different types of SSEs as well as the corresponding optimization strategies are first highlighted. Then, the state-of-the-art preparation methods and properties of different kinds of SSE materials, and their manufacture, characterization and performance in SSLSBs are summarized in detail. Finally, a scientific outlook for the future development of SSEs and the avenue to commercial application of SSLSBs is also proposed.

Synergistic Interfacial Bonding in Reduced Graphene Oxide Fiber Cathodes Containing Polypyrrole@sulfur Nanospheres for Flexible Energy Storage.

Flexible lithium sulfur batteries with high energy density and good mechanical flexibility are highly desirable. Here, we report a synergistic interface bonding enhancement strategy to construct flexible fiber-shaped composite cathodes, in which polypyrrole@sulfur (PPy@S) nanospheres are homogeneously implanted into the built-in cavity of self-assembled reduced graphene oxide fibers (rGOFs) by a facile microfluidic assembly method. In this architecture, sulfur nanospheres and lithium polysulfides are synergistically hosted by carbon and polymer interface, which work together to provide enhanced interface chemical bonding to endow the cathode with good adsorption ability, fast reaction kinetics, and excellent mechanical flexibility. Consequently, the PPy@S/rGOFs cathode shows enhanced electrochemical performance and high-rate capability. COMSOL Multiphysics simulations and density functional theory (DFT) calculations are conducted to elucidate the enhanced electrochemical performance. In addition, a flexible Li-S pouch cell is assembled and delivers a high areal capacity of 5.8 mAh cm-2 at 0.2 A g-1 . Our work offers a new strategy for preparation of advanced cathodes for flexible batteries.

Single-Crystal-Layered Ni-Rich Oxide Modified by Phosphate Coating Boosting Interfacial Stability of Li10 SnP2 S12 -Based All-Solid-State Li Batteries.

All-solid-state lithium batteries (ASSLBs) adopting sulfide electrolytes and high-voltage layered oxide cathodes have moved into the mainstream owing to their superior safety and immense potential in high energy density. However, the poor electrochemical compatibility between oxide cathodes and sulfide electrolytes remains a challenge for high-performance ASSLBs. In this study, a nanoscale Li1.4 Al0.4 Ti1.6 (PO4 )3 (LATP) phosphate coating is reasonably constructed on the surface of single-crystal LiNi0.6 Co0.2 Mn0.2 O2 particles to achieve cathode/electrolyte interfacial stability. The conformal LATP layer with inherent high-voltage stability can effectively suppress the oxidation decomposition of the electrolyte and demonstrate chemical inertness to both the oxide cathode and Li10 SnP2 S12 electrolyte. ASSLBs with an LATP-modified cathode exhibited a high initial discharge capacity (152.1 mAh g-1 ), acceptable rate capability, and superior cycling performance with a capacity retention of 87.6% after 100 cycles at 0.1 C. Interfacial modification is an effective approach for achieving high-performance sulfide-based ASSLBs with superior interfacial stability.

An Inorganic-Rich Solid Electrolyte Interphase for Advanced Lithium-Metal Batteries in Carbonate Electrolytes.

In carbonate electrolytes, the organic-inorganic solid electrolyte interphase (SEI) formed on the Li-metal anode surface is strongly bonded to Li and experiences the same volume change as Li, thus it undergoes continuous cracking/reformation during plating/stripping cycles. Here, an inorganic-rich SEI is designed on a Li-metal surface to reduce its bonding energy with Li metal by dissolving 4m concentrated LiNO3 in dimethyl sulfoxide (DMSO) as an additive for a fluoroethylene-carbonate (FEC)-based electrolyte. Due to the aggregate structure of NO3 - ions and their participation in the primary Li+ solvation sheath, abundant Li2 O, Li3 N, and LiNx Oy grains are formed in the resulting SEI, in addition to the uniform LiF distribution from the reduction of PF6 - ions. The weak bonding of the SEI (high interface energy) to Li can effectively promote Li diffusion along the SEI/Li interface and prevent Li dendrite penetration into the SEI. As a result, our designed carbonate electrolyte enables a Li anode to achieve a high Li plating/stripping Coulombic efficiency of 99.55 % (1 mA cm-2 , 1.0 mAh cm-2 ) and the electrolyte also enables a Li||LiNi0.8 Co0.1 Mn0.1 O2 (NMC811) full cell (2.5 mAh cm-2 ) to retain 75 % of its initial capacity after 200 cycles with an outstanding CE of 99.83 %.

High Interfacial-Energy Interphase Promoting Safe Lithium Metal Batteries.

Engineering a stable solid electrolyte interphase (SEI) is critical for suppression of lithium dendrites. However, the formation of a desired SEI by formulating electrolyte composition is very difficult due to complex electrochemical reduction reactions. Here, instead of trial-and-error of electrolyte composition, we design a Li-11 wt % Sr alloy anode to form a SrF2-rich SEI in fluorinated electrolytes. Density functional theory (DFT) calculation and experimental characterization demonstrate that a SrF2-rich SEI has a large interfacial energy with Li metal and a high mechanical strength, which can effectively suppress the Li dendrite growth by simultaneously promoting the lateral growth of deposited Li metal and the SEI stability. The Li-Sr/Cu cells in 2 M LiFSI-DME show an outstanding Li plating/stripping Coulombic efficiency of 99.42% at 1 mA cm-2 with a capacity of 1 mAh cm-2 and 98.95% at 3 mA cm-2 with a capacity of 2 mAh cm-2, respectively. The symmetric Li-Sr/Li-Sr cells also achieve a stable electrochemical performance of 180 cycles at an extremely high current density of 30 mA cm-2 with a capacity of 1 mAh cm-2. When paired with LiFePO4 (LFP) and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes, Li-Sr/LFP cells in 2 M LiFSI-DME electrolytes and Li-Sr/NMC811 cells in 1 M LiPF6 in FEC:FEMC:HFE electrolytes also maintain excellent capacity retention. Designing SEIs by regulating Li-metal anode composition opens up a new and rational avenue to suppress Li dendrites.

Anchoring SnS2 on TiC/C Backbone to Promote Sodium Ion Storage by Phosphate Ion Doping.

Tin disulfide (SnS2 ) shows promising properties toward sodium ion storage with high capacity, but its cycle life and high rate capability are still undermined as a result of poor reaction kinetics and unstable structure. In this work, phosphate ion (PO4 3- )-doped SnS2 (P-SnS2 ) nanoflake arrays on conductive TiC/C backbone are reported to form high-quality P-SnS2 @TiC/C arrays via a hydrothermal-chemical vapor deposition method. By virtue of the synergistic effect between PO4 3- doping and conductive network of TiC/C arrays, enhanced electronic conductivity and enlarged interlayer spacing are realized in the designed P-SnS2 @TiC/C arrays. Moreover, the introduced PO4 3- can result in favorable intercalation/deintercalation of Na+ and accelerate electrochemical reaction kinetics. Notably, lower bandgap and enhanced electronic conductivity owing to the introduction of PO4 3- are demonstrated by density function theory calculations and UV-visible absorption spectra. In view of these positive factors above, the P-SnS2 @TiC/C electrode delivers a high capacity of 1293.5 mAh g-1 at 0.1 A g-1 and exhibits good rate capability (476.7 mAh g-1 at 5 A g-1 ), much better than the SnS2 @TiC/C counterpart. This work may trigger new enthusiasm on construction of advanced metal sulfide electrodes for application in rechargeable alkali ion batteries.

Enhanced bioaccumulation efficiency and tolerance for Cd (â ¡) in Arabidopsis thaliana by amphoteric nitrogen-doped carbon dots.

Amphoteric nitrogen-doped carbon dots (N-CDs) that prepared environmentally friendly have rich functional groups, such as carboxyl, amino, hydroxyl, carbonyl, etc. Through electrostatic attraction and complexation between the chemical groups and metal ions, N-CDs present excellent adsorption capacity for Cd2+ in heavy polluted water with the saturated adsorption weight of 559  mg g-1. The investigation of interaction between N-CDs, Cd2+ and Arabidopsis thaliana reveals that N-CDs (from 4  mg kg-1 to 8  mg kg-1) can dramatically enhance Cd bioaccumulation of plants by 58.3% of unit biomass and 260% of individual seedling when the plants were cultivated for 10 days under Cd stress (from 10 mg kg-1 to 50 mg kg-1). Simultaneously, N-CDs significantly alleviate the toxicity caused by high Cd stress on Arabidopsis thaliana seedlings growth. N-CDs induce higher germination rate (maximum: 2.5-fold), higher biomass (maximum: 3.7-fold), better root development (maximum: 1.4-fold), higher photosynthetic efficiency and higher antioxidant capacity in plants under Cd stress. When the Cd and N-CDs concentration are respective 20 mg kg-1 and 4 mg kg-1, the enzyme activities of the catalase and peroxidase increased to 2.73-fold and 1.45-fold, respectively. This research prove the potential application of amphoteric N-CDs in phytoremediation because N-CDs greatly mitigate the growth retardation of plant caused by Cd2+ even with the extremely increased Cd2+ concentration in vivo.

Impacts of surface chemistry of functional carbon nanodots on the plant growth.

Functional carbon nanodots (FCNs) with multiple chemical groups have great impact on the growth regulation of plants. To understand the role of the chemical groups, FCNs were reduced from the raw material by pyrolysis method and hydrolysis method. The chemical structure of these materials were characterized by using TGA, TEM, FT-IR, XPS, Raman and elementary analysis. The raw and reduced FCNs were used as plants growth regulators in culture medium of Arabidopsis thaliana. Our results indicate there is a strong correlation between the physiological responses of plants and the surface chemistries (especially carboxyl group and ester group) of the nanomaterials. The quantum-sized FCNs with multiple carboxyl groups and ester groups show better aqueous dispersity and can induce various positive physiological responses in Arabidopsis thaliana seedlings compared with the FCNs decorated without carboxyl and ester as well as aggregated FCNs. The raw FCNs present higher promotion capacity in plants biomass and roots length, and the quantum-sized FCNs are easier to be absorbed by plants and generate more positive effects on plants.

Boosting High-Rate Sodium Storage Performance of N-Doped Carbon-Encapsulated Na3 V2 (PO4 )3 Nanoparticles Anchoring on Carbon Cloth.

The further development of high-power sodium-ion batteries faces the severe challenge of achieving high-rate cathode materials. Here, an integrated flexible electrode is constructed by smart combination of a conductive carbon cloth fiber skeleton and N-doped carbon (NC) shell on Na3 V2 (PO4 )3 (NVP) nanoparticles via a simple impregnation method. In addition to the great electronic conductivity and high flexibility of carbon cloth, the NC shell also promotes ion/electron transport in the electrode. The flexible NVP@NC electrode renders preeminent rate capacities (80.7 mAh g-1 at 50 C for cathode; 48 mAh g-1 at 30 C for anode) and superior cycle performance. A flexible symmetric NVP@NC//NVP@NC full cell is endowed with fairly excellent rate performance as well as good cycle stability. The results demonstrate a powerful polybasic strategy design for fabricating electrodes with optimal performance.

Ti3+ Self-Doped Li4 Ti5 O12 Anchored on N-Doped Carbon Nanofiber Arrays for Ultrafast Lithium-Ion Storage.

Omnibearing acceleration of charge/ion transfer in Li4 Ti5 O12 (LTO) electrodes is of great significance to achieve advanced high-rate anodes in lithium-ion batteries. Here, a synergistic combination of hydrogenated LTO nanoparticles (H-LTO) and N-doped carbon fibers (NCFs) prepared by an electrodeposition-atomic layer deposition method is reported. Binder-free conductive NCFs skeletons are used as strong support for H-LTO, in which Ti3+ is self-doped along with oxygen vacancies in LTO lattice to realize enhanced intrinsic conductivity. Positive advantages including large surface area, boosted conductivity, and structural stability are obtained in the designed H-LTO@NCF electrode, which is demonstrated with preeminent high-rate capability (128 mAh g-1 at 50 C) and long cycling life up to 10 000 cycles. The full battery assembled by H-LTO@NCFs anode and LiFePO4 cathode also exhibits outstanding electrochemical performance revealing an encouraging application prospect. This work further demonstrates the effectiveness of self-doping of metal ions on reinforcing the high-rate charge/discharge capability of batteries.

Enhanced Li-Storage of Ni3 S2 Nanowire Arrays with N-Doped Carbon Coating Synthesized by One-Step CVD Process and Investigated Via Ex Situ TEM.

In this work, a facile strategy for the construction of single crystalline Ni3 S2 nanowires coated with N-doped carbon shell (NC) forming Ni3 S2 @NC core/shell arrays by one-step chemical vapor deposition process is reported. In addition to the good electronic conductivity from the NC shell, the nanowire structure also ensures the accommodation of large volume expansion during cycling, leading to pre-eminent high-rate capacities (470 mAh g-1 at 0.05 A g-1 and 385 mAh g-1 at 2 A g-1 ) and outstanding cycling stability with a capacity retention of 91% after 100 cycles at 1 A g-1 . Furthermore, ex situ transmission electron microscopy combined with X-ray diffraction and Raman spectra are used to investigate the reaction mechanism of Ni3 S2 @NC during the charge/discharge process. The product after delithiation consists of Ni3 S2 and sulfur, suggesting that the capacity of the electrode comes from the conversion reaction of both Ni3 S2 and sulfur with Li2 S.

Coupled Biphase (1T-2H)-MoSe2 on Mold Spore Carbon for Advanced Hydrogen Evolution Reaction.

Performance breakthrough of MoSe2 -based hydrogen evolution reaction (HER) electrocatalysts largely relies on sophisticated phase modulation and judicious innovation on conductive matrix/support. In this work the controllable synthesis of phosphate ion (PO43- ) intercalation induced-MoSe2 (P-MoSe2 ) nanosheets on N-doped mold spore carbon (N-MSC) forming P-MoSe2 /N-MSC composite electrocatalysts is realized. Impressively, a novel conductive N-MSC matrix is constructed by a facile mold fermentation method. Furthermore, the phase of MoSe2 can be modulated by a simple phosphorization strategy to realize the conversion from 2H-MoSe2 to 1T-MoSe2 to produce biphase-coexisted (1T-2H)-MoSe2 by PO43- intercalation (namely, P-MoSe2 ), confirmed by synchrotron radiation technology and spherical aberration-corrected TEM (SACTEM). Notably, higher conductivity, lower bandgap and adsorption energy of H+ are verified for the P-MoSe2 /N-MSC with the help of density functional theory (DFT) calculation. Benefiting from these unique advantages, the P-MoSe2 /N-MSC composites show superior HER performance with a low Tafel slope (≈51 mV dec-1 ) and overpotential (≈126 mV at 10 mA cm-1 ) and excellent electrochemical stability, better than 2H-MoSe2 /N-MSC and MoSe2 /carbon nanosphere (MoSe2 /CNS) counterparts. This work demonstrates a new kind of carbon material via biological cultivation, and simultaneously unravels the phase transformation mechanism of MoSe2 by PO43- intercalation.

Defect Promoted Capacity and Durability of N-MnO2- x Branch Arrays via Low-Temperature NH3 Treatment for Advanced Aqueous Zinc Ion Batteries.

Defect engineering (doping and vacancy) has emerged as a positive strategy to boost the intrinsic electrochemical reactivity and structural stability of MnO2 -based cathodes of rechargeable aqueous zinc ion batteries (RAZIBs). Currently, there is no report on the nonmetal element doped MnO2 cathode with concomitant oxygen vacancies, because of its low thermal stability with easy phase transformation from MnO2 to Mn3 O4 (≥300 °C). Herein, for the first time, novel N-doped MnO2- x (N-MnO2- x ) branch arrays with abundant oxygen vacancies fabricated by a facile low-temperature (200 °C) NH3 treatment technology are reported. Meanwhile, to further enhance the high-rate capability, highly conductive TiC/C nanorods are used as the core support for a N-MnO2- x branch, forming high-quality N-MnO2- x @TiC/C core/branch arrays. The introduced N dopants and oxygen vacancies in MnO2 are demonstrated by synchrotron radiation technology. By virtue of an integrated conductive framework, enhanced electron density, and increased surface capacitive contribution, the designed N-MnO2- x @TiC/C arrays are endowed with faster reaction kinetics, higher capacity (285 mAh g-1 at 0.2 A g-1 ) and better long-term cycles (85.7% retention after 1000 cycles at 1 A g-1 ) than other MnO2 -based counterparts (55.6%). The low-temperature defect engineering sheds light on construction of advanced cathodes for aqueous RAZIBs.

Porous Carbon Hosts for Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) are considered to be one of the most promising alternatives to the current lithium-ion batteries (LIBs) to meet the increasing demand for energy storage owing to their high energy density, natural abundance, low cost, and environmental friendliness. Despite great success, LSBs still suffer from several problems, including undermined capacity arising from low utilization of sulfur, unsatisfactory rate performance and poor cycling life owing to the shuttle effect of polysulfides, and poor electrical conductivity of sulfur. Under such circumstances, the design/fabrication of porous carbon-sulfur composite cathodes is regarded as an effective solution to overcome the above problems. In this review, different synthetic methods of porous carbon hosts and their corresponding integration into carbon-sulfur cathodes are summarized. The pore formation mechanism of porous carbon hosts is also addressed. The pore size effect on electrochemical performance is highlighted and compared. The enhanced mechanism of the porous carbon host on the sulfur cathode is systematically reviewed and revealed. Finally, the combination of porous carbon hosts and high-profile solid-state electrolytes is demonstrated, and the challenges to realize large-scale commercial application of porous carbon-sulfur cathodes is discussed and future trends are proposed.

Synergistic Doping and Intercalation: Realizing Deep Phase Modulation on MoS2 Arrays for High-Efficiency Hydrogen Evolution Reaction.

A synergistic N doping plus PO4 3- intercalation strategy is used to induce high conversion (ca. 41 %) of 2H-MoS2 into 1T-MoS2 , which is much higher than single N doping (ca. 28 %) or single PO4 3- intercalation (ca. 10 %). A scattering mechanism is proposed to illustrate the synergistic phase transformation from the 2H to the 1T phase, which was confirmed by synchrotron radiation and spherical aberration TEM. To further enhance reaction kinetics, the designed (N,PO4 3- )-MoS2 nanosheets are combined with conductive vertical graphene (VG) skeleton forming binder-free arrays for high-efficiency hydrogen evolution reaction (HER). Owing to the decreased band gap, lower d-band center, and smaller hydrogen adsorption/desorption energy, the designed (N,PO4 3- )-MoS2 /VG electrode shows excellent HER performance with a lower Tafel slope and overpotential than N-MoS2 /VG, PO4 3- -MoS2 /VG counterparts, and other Mo-base catalysts in the literature.