Excellent Interfacial Contact Research Articles

Corrosion Resistance and Conductivity of Ta-Nb-N-Coated 316L Stainless Steel as Bipolar Plates for Proton Exchange Membrane Fuel Cells

The large-scale application of stainless steel (SS) bipolar plates (BPs) in proton exchange membrane fuel cells (PEMFCs) is mainly limited by insufficient corrosion resistance and electrical conductivity. In this work, Ta-Nb-N coatings were prepared on 316L SS substrates by unbalanced magnetron sputtering to improve corrosion resistance and conductivity. The Ta-Nb-N coatings had a dense structure without obvious defects. In simulated PEMFC cathode environments consisting of 0.5 M H2SO4 + 2 ppm HF at 70 ± 0.5 °C, which is harsher than the U.S. Department of Energy specification, the corrosion current density of Ta-Nb-N-coated BPs was reduced to 2.2 × 10−2 μA·cm−2. Ta-Nb-N-coated samples showed better electrical conductivity than 316L SS, which had an excellent interfacial contact resistance of 9.2 mΩ·cm2. In addition, the Ta-Nb-N-coated samples had a water contact angle of 100.7°, showing good hydrophobicity for water management. These results indicate that Ta-Nb-N coatings could be a promising material for BPs.

Flat-tube solid oxide stack with high performance for power generation and hydrogen production

This study presents the design, fabrication, and evaluation of a high-performance flat-tube solid oxide cell (FT-SOC) stack, which demonstrates exceptional power generation and hydrogen production capabilities. Comprising three large-sized FT-SOCs, each with an active area of 60 cm2, the stack was tested at 750 °C. It achieved a peak power density of 1.222 W/cm2 in fuel cell (FC) mode and an electrolysis current density of 1.283 A/cm2 at an average voltage of 1.3 V in electrolysis cell (EC) mode, marking the highest reported values for FT-SOC stacks to date. These results surpass the performance of most large-sized planar SOC stacks. Post-operation analysis revealed excellent interfacial contact between components, contributing to the stack's high performance. This study underscores the potential of FT-SOCs in efficient power generation and electrolytic energy storage applications, providing insights that could facilitate their industrial application.

Electrical and ionic conductivity of Li2O-B2O3-Al2O3 glass electrolyte for solid-state batteries

Solid-state electrolyte is a key component for all-solid-state lithium-ion batteries. The Li2O-B2O3-Al2O3 has been prepared, which is co-sinterable with electrode due to its low sintering temperature (520 °C). The as-prepared Li2O-B2O3-Al2O3 reveals glass transition temperature of 420 °C and crystallization temperature of 462 °C. The Li2O-B2O3-Al2O3 possess the reasonable electrochemical performances such as lithium-ion conductivity of 3.075 × 10−5 S/cm, activation energy of 0.72 eV, electronic conductivity of 4.102 × 10−5 S/cm. It is attributed to the particle morphology, grain-to-grain bonding and non-bridging oxygen. Our finding demonstrates that Li2O-B2O3-Al2O3 is an effective breakthrough in solid electrolyte for good electrochemical performances as well as excellent interfacial contact through co-sintering.

Solid-state magic: How Bi2O3 and V2O5 combine to create a high-performance photoanode for water oxidation

A simple method to create a BiVO4–V2O5 photoanode with excellent interfacial contact and self-doping with V4+ and oxygen vacancies was proposed in this study. Direct generation of BiVO4 within the film through a solid state reaction between Bi2O3 and V2O5 was achieved, resulting in a highly efficient charge separation and a photocurrent density of 6.6 mA cm−2 at 1.23 V vs. RHE. The bulk charge separation efficiency was 95 %. This study highlights the importance of good interfacial contact for suppressing charge recombination and enabling efficient water oxidation. The developed synthesis method can be a practical approach for fabricating advanced photoelectrodes for sustainable water-splitting technologies, enabling carbon-free fuel production.

Gel electrolyte and anode material derived from electro-spun polyacrylonitrile/polysilsesquioxane composite and application in advanced lithium-ion batteries

The aim of this work is to improve the comprehensive performance of Lithium-ion batteries (LIBs) by designing and fabricating novel polymer electrolyte. A flexible film composed of electro-spun polyacrylonitrile/1,2-ethylidene-bridged polysilsesquioxane composite nanofibers (PAN@ee-PSiO) was synthesized via a sol–gel method, and then used as scaffold to absorb organic electrolyte to make gel electrolyte membrane (PAN@ee-PSiO-GE). It presents high electrolyte uptake (472 wt%), thermal stability (up to ∼300 °C), high ionic conductivity (∼7.2 mS cm−1 at room temperature) and excellent interfacial contact with Li metal electrodes. Meanwhile, Si/SiC/C composite nanofibers (SSCNFs) were also produced from PAN/ee-PSiO film by magnesiothermic reduction and could act as anode material. The assembled SSCNFs|PAN@ee-PSiO-GE|Li half-cell exhibits excellent rate capability and good cycling stability, indicating a new way for designing and fabricating safer high-performance LIBs.

Sandwiched composite electrolyte with excellent interfacial contact for high-performance solid-state sodium-ion batteries

Solid-state sodium-ion batteries have attracted significant attention due to their rich resources, high safety, and high energy density. However, the lower ionic conductivity and inferior interfacial contact between solid-state electrolytes (SSEs) and electrodes limit their practical applications. Herein, polyvinylideneuoride-co-hexauoropropylene (PVDF-HFP) membrane is selected and a novel sandwiched composite PVDF-HFP/Na2.5Zr1.95Ce0.05Si2.2P0.8O11.3F0.7/PVDF-HFP (G-NZC0.05SPF0.7-G) SSEs is well designed. The ionic conductivity of Na3Zr2Si2PO12 is enhanced by Ce4+/F− co-doping. The effects of Ce4+ and F− doping on the crystal structure, density, and ionic conductivity for Na3Zr2Si2PO12 are well investigated. The optimal NZC0.05SPF0.7 delivers a high ionic conductivity of 1.39 × 10−3 S cm−1 at 25 ℃. Moreover, the PVDF-HFP membrane can significantly enhance the interface compatibility between NZC0.05SPF0.7 and electrodes. The as-prepared G-NZC0.05SPF0.7-G exhibits a large ionic conductivity of 1.07 × 10−3 S cm−1 at 25 ℃, wide electrochemical stability window up to 4.5 V, high critical current density of 1.2 A cm−2, and stable Na plating/stripping over 600 h at 0.3 A cm−2. The solid-state Na0.67Mn0.47Ni0.33Ti0.2O2/G-NZC0.05SPF0.7-G/Na battery delivers a remarkable cycling stability and rate capability at 25 ℃, indicating that the as-prepared G-NZC0.05SPF0.7-G has a promising application for solid-state SIBs. This study demonstrates an effective strategy to develop advanced solid-state electrolytes for solid-state SIBs.

Improvement in Corrosion Resistance and Interfacial Contact Resistance Properties of 316L Stainless Steel by Coating with Cr, Ti Co-Doped Amorphous Carbon Films in the Environment of the PEMFCs.

In order to obtain films with high corrosion resistance and excellent interfacial contact resistance (ICR) on 316L stainless steel used for bipolar plates in proton-exchange membrane fuel cells (PEMFCs), Cr, Ti co-doped amorphous carbon films were prepared on 316L stainless steel. The preparation method for the coating was magnetron sputtering. The doping amount of the Ti element was controlled by a Cr target and a Ti target current. The change in the structure and properties of the coating after the change from Cr single-element doping to Cr and Ti co-doping was studied. The change rule of the structure and properties of the coating from Cr single-element doping to Cr and Ti co-doping was studied. An increase in the Ti content led to a decreased grain boundary, a flatter surface, and a higher sp2-hybridized carbon content. TiC and CrC nanocrystals were formed in the amorphous carbon structure together. The amorphous carbon films doped with Cr and Ti simultaneously achieved a low ICR and high corrosion resistance compared with single-Cr-doped amorphous carbon. The enhanced corrosion resistance was attributed to the decreasing grain boundary, the formation of the TiC crystal structure, and the smaller grain size. The best performance was obtained at a Ti target current of 2A. Compared with bare 316L stainless steel, the corrosion resistance of Cr, Ti co-doped amorphous carbon (Icorr = 5.7 × 10-8 A/cm2, Ti-2 sample) was greatly improved. Because Ti doping increased the content of sp2-hybridized carbon in the coating, the contact resistance of the coating decreased. Moreover, the interfacial contact resistance was 3.1 mΩ·cm2 in the Ti-2 sample, much lower than that of bare 316L stainless steel. After the potentiostatic polarization test, the coating still had excellent conductivity.

In Situ Polymerized 1,3‐Dioxolane Electrolyte for Integrated Solid‐State Lithium Batteries

AbstractSolid‐state lithium batteries are promising and safe energy storage devices for mobile electronics and electric vehicles. In this work, we report a facile in situ polymerization of 1,3‐dioxolane electrolytes to fabricate integrated solid‐state lithium batteries. The in situ polymerization and formation of solid‐state dioxolane electrolytes on interconnected carbon nanotubes (CNTs) and active materials is the key to realizing a high‐performance battery with excellent interfacial contact among CNTs, active materials and electrolytes. Therefore, the electrodes could be tightly integrated into batteries through the CNTs and electrolyte. Electrons/ions enable full access to active materials in the whole electrode. Electrodes with a low resistance of 4.5 Ω □−1 and high lithium‐ion diffusion efficiency of 2.5×10−11 cm2 s−1 can significantly improve the electrochemical kinetics. Subsequently, the batteries demonstrated high energy density, amazing charge/discharge rate and long cycle life.

In Situ Polymerized 1,3-Dioxolane Electrolyte for Integrated Solid-State Lithium Batteries.

Solid-state lithium batteries are promising and safe energy storage devices for mobile electronics and electric vehicles. In this work, we report a facile in situ polymerization of 1,3-dioxolane electrolytes to fabricate integrated solid-state lithium batteries. The in situ polymerization and formation of solid-state dioxolane electrolytes on interconnected carbon nanotubes (CNTs) and active materials is the key to realizing a high-performance battery with excellent interfacial contact among CNTs, active materials and electrolytes. Therefore, the electrodes could be tightly integrated into batteries through the CNTs and electrolyte. Electrons/ions enable full access to active materials in the whole electrode. Electrodes with a low resistance of 4.5 Ω □-1 and high lithium-ion diffusion efficiency of 2.5×10-11 cm2 s-1 can significantly improve the electrochemical kinetics. Subsequently, the batteries demonstrated high energy density, amazing charge/discharge rate and long cycle life.

High ionic conducting rare-earth silicate electrolytes for sodium metal batteries

Sodium gadolinium silicate solid electrolyte showed an outstanding sodium plating/stripping performance for 1000 cycles that proves excellent interfacial contact between the sodium anode and solid electrolyte.

Thin-film composite mixed-matrix membrane with irregular micron-sized UTSA-16 for outstanding gas separation performance

Low-cost, micron-sized particles still pose a barrier to their use in thin-film composite mixed-matrix membranes (TFC-MMMs) owing to their poor interfacial contact with the polymer matrix. Also, the particles are too large to be fabricated into the submicron-thick membranes. Herein, we report high-performing, TFC-MMMs based on a CO2-philic comb copolymer, poly (tetrahydrofurfuryl methacrylate)–co–poly (poly (oxyethylene methacrylate)) (PTO), and an irregular, micron-sized, CO2-selective metal-organic framework (MOF), UTSA-16. The PTO comb copolymer matrix exhibited excellent film-forming ability, adhesion properties and showed a good gas separating performance. The PTO comb copolymer also enhanced the dispersibility of UTSA-16 in an environment-friendly solvent mixture (i.e., ethanol/water), which did not adversely damage the underlying porous polymeric support. Despite the micron-scale particle size of UTSA-16, PTO copolymer completely covered the surface of UTSA-16 via strong interactions without any deep pore infiltration and exhibited excellent interfacial contact properties. Consequently, defect-free TFC-MMMs with a polymer thickness of 300 nm were successfully prepared on the porous support. The TFC-MMM with 10% filler loading exhibited excellent CO2 permeance and selectivity, i.e., CO2 permeance of 1070 GPU, CO2/N2 selectivity of 41.0, CO2/CH4 selectivity of 17.2, outperforming the TFC-MMMs prepared with commercially available Pebax. All PTO-based MMMs, with the exception of the low content of UTSA-16 (5%), exceeded the gas separation performance required for post-combustion CO2 capture process.

Near Room-Temperature Synthesis of Vertical Graphene Nanowalls on Dielectrics.

Vertical graphene nanowalls (VGNs) with excellent heat-transfer properties are promising to be applied in the thermal management of electronic devices. However, high growth temperature makes VGNs unable to be directly prepared on semiconductors and polymers, which limits the practical application of VGNs. In this work, the near room-temperature growth of VGNs was realized by utilizing the hot filament chemical vapor deposition method. Catalytic tantalum (Ta) filaments promote the decomposition of acetylene at ∼1600 °C. Density functional theory calculations proved that C2H* was the main active carbon cluster during VGN growth. The restricted diffusion of C2H* clusters induced the vertical growth of graphene nanoflakes on various substrates below 150 °C. The direct growth of VGNs successfully realized the excellent interfacial contact, and the thermal contact resistance could reach 3.39 × 10-9 m2·K·W-1. The temperature of electronic chips had a 6.7 °C reduction by utilizing directly prepared VGNs instead of thermal conductive tape as thermal-interface materials, indicating the great potential of VGNs to be directly prepared on electronic devices for thermal management.

Constructing S-scheme heterojunction of carbon nitride nanorods (g-CNR) assisted trimetallic CoAlLa LDH nanosheets with electron and holes moderation for boosting photocatalytic CO2 reduction under solar energy

• Fabrication of 1D/2D g-CNR and trimetallic CoAlLa-LDH heterojunction for CO 2 reduction. • 1D g-CNR provides extra active reaction place and permits fast photogenerated charge carriers separation. • 2D/2D g-CNR/CoAlLa-LDH interface heterojunction showed S-scheme mechanism for efficient CO 2 reduction. • The photocatalytic bireforming of methane resulted in syngas (CO/H 2 ) evolution. • The enhanced visible light activity attributed to the formation of S-scheme with good stability. Well-designed template free synthesis of one dimensional (1D) graphitic carbon nitride nanorods (g-CNR) coupled with two dimensional (2D) trimetallic CoAlLa-LDH to construct 1D/2D interface heterostructures with strong electrostatic interactions between positively charged 2D LDH sheets and negatively charged 1D g-CNR has been investigated. The lanthanum doped CoAlLa-LDH with unsaturated metal centers has increased reductive sites and oxygen vacancies that led to enhanced charge separation. The 1D g-CNR provides extra active reaction sites for the photocatalytic reaction and permit fast photogenerated charge carriers separation across the interface. The coupling of g-CNR and CoAlLa-LDH with excellent properties resulted in 1D/2D interface heterojunction with S-scheme mechanism for charge carrier transfer by maintaining and effectively utilizing useful charge carriers. The 1D/2D g-CNR/CoAlLa-LDH showed remarkable photocatalytic performance for CO 2 reduction with H 2 O resulting in maximum CO and CH 4 production of 17.85 and 14.66 µmole, respectively. The photocatalytic bireforming (BRM) of methane resulted in the production of syngas (CO/H 2 ) with 12.32 and 5.96 µmole of CO and H 2 , respectively. The enhancement of photocatalytic activity is mainly due to the excellent interfacial contact of g-CNR with ternary metallic CoAlLa-LDH, thus resulting in better transfer and separation of photogenerated charge carriers due to the formation of S-scheme heterojunction. Additionally, the optimum g-CNR/CoAlLa-LDH nanocomposite acquired high photostability after consecutive experimental runs with no apparent variation. The spent catalyst showed no change in morphology, thus proving further good stability of the g-CNR/CoAlLa-LDH photocatalyst. The findings of this work would be beneficial to design template free heterojunction for photocatalytic CO 2 reduction and other solar energy application.

Flexible composite solid electrolyte with 80 wt% Na3.4Zr1.9Zn0.1Si2.2P0.8O12 for solid-state sodium batteries

Composite solid electrolyte (CSE) with high ceramic content has received extensive attention due to the combined advantages of ceramic electrolyte and flexible polymer component as well as superior thermal stability and mechanical properties. However, high ionic conductivity, desired flexibility and excellent electrolyte-electrode interfacial contact are huge challenges. Herein, a flexible, non-flammable and high ion conductive NASICON CSE with 80 wt% Na3.4Zr1.9Zn0.1Si2.2P0.8O12 particles in polyethylene oxide is realized through coupling with trace amount of ionic liquid into the CSE. The resultant NASICON CSE delivers high ionic conductivity of 1.48 × 10−4 S cm−1 at 25 °C, outstanding thermal stability and good interfacial stability against sodium metal. Benefiting from these merits, the assembled Na3V2(PO4)3//Na solid-state sodium batteries demonstrate excellent rate performances and cycling stability with a capacity retention of 90.0% after 150 cycles at 0.5 C under 60 °C. The Na3V2(PO4)3//Na battery further exhibits an initial discharge capacity of 109.4 mAh g−1 with a capacity retention of 85.4% after 150 cycles at 0.2 C under 25 °C. Moreover, the Na3V2(PO4)3//Na pouch battery exhibits impressive flexibility and safety. This work provides a promising strategy to realize flexible, non-flammable and high ion conductive NASICON CSE with high content of NASICON component for solid-state sodium batteries.

Enhancing Interfacial Contact in Solid-State Batteries with a Gradient Composite Solid Electrolyte.

Solid-state batteries promise to meet the challenges of high energy density and high safety for future energy storage. However, poor interfacial contact and complex manufacturing processes limit their practical applications. Herein, a simple strategy is proposed to enhance interfacial contact by introducing a gradient composite polymer solid electrolyte (GCPE), which is prepared by a facile UV-curing polymerization technique. The high-Li6.4 La3 Zr1.4 Ta0.6 O12 (LLZTO)-content side of the electrolyte exhibits high oxidation resistance (5.4V versus Li+ /Li), making it compatible with a high-voltage cathode material, whereas the LLZTO-deficient side achieves excellent interfacial contact with the Li metal anode, facilitating uniform Li deposition. Benefiting from the elaborate composition and structure of GCPE films, the symmetric Li//Li cell exhibits a low-voltage hysteresis potential of 42mV and a long cycle life of >1900h without short-circuiting. The Li//LiFePO4 solid-state batteries deliver a capacity of 161.0mA h g-1 at 60 °C and 0.1 C (82.4% capacity is retained after 200 cycles). Even at 80 °C, the cell still shows an outstanding capacity of 132.9 mAh g-1 at 0.2 C after 100 cycles. The design principle of gradient electrolytes provides a new path for achieving enhanced interfacial contact in high-performance solid-state batteries.

Inorganic Fillers in Composite Gel Polymer Electrolytes for High-Performance Lithium and Non-Lithium Polymer Batteries.

Among the various types of polymer electrolytes, gel polymer electrolytes have been considered as promising electrolytes for high-performance lithium and non-lithium batteries. The introduction of inorganic fillers into the polymer-salt system of gel polymer electrolytes has emerged as an effective strategy to achieve high ionic conductivity and excellent interfacial contact with the electrode. In this review, the detailed roles of inorganic fillers in composite gel polymer electrolytes are presented based on their physical and electrochemical properties in lithium and non-lithium polymer batteries. First, we summarize the historical developments of gel polymer electrolytes. Then, a list of detailed fillers applied in gel polymer electrolytes is presented. Possible mechanisms of conductivity enhancement by the addition of inorganic fillers are discussed for each inorganic filler. Subsequently, inorganic filler/polymer composite electrolytes studied for use in various battery systems, including Li-, Na-, Mg-, and Zn-ion batteries, are discussed. Finally, the future perspectives and requirements of the current composite gel polymer electrolyte technologies are highlighted.

In situ generation of a soft–tough asymmetric composite electrolyte for dendrite-free lithium metal batteries

Asymmetric CPE was prepared by utilizing the natural settlement of LLZAO during the monomer polymerization process. This asymmetric CPE can successfully achieve both excellent interfacial contact with electrodes and dendrite suppression of Li anode.

Hydrothermal synthesis of Bi2O4/NaBiO3 heterostructures with enhanced visible light photocatalytic properties

Novel Bi2O4/NaBiO3 heterostructures were fabricated via a hydrothermal process. By controlling the reaction time, part of NaBiO3 could be in-situ transformed into Bi2O4, which endowed the obtained heterostructures with excellent interfacial contact. The heterostructures were characterized by using XRD, FT-IR, XPS, SEM, EDS mapping and DRS. Degradation of methyl orange (MO) and phenol was used to evaluate the photocatalytic activities of the samples under visible light irradiation. Bi2O4/NaBiO3 heterostructures exhibited enhanced photocatalytic performance compared with bare NaBiO3 and Bi2O4. The increased activity could be attributed to the effective separation and transfer of electron-hole pairs in type II Bi2O4/NaBiO3 heterojunction, which were confirmed by PL and photoelectrochemical tests. Meanwhile, the EPR and trapping experiments revealed that h+ and •O2− played a main role in the photocatalytic degradation reaction.

Ultrathin, flexible, and sandwiched structure composite polymer electrolyte membrane for solid-state lithium batteries

Solid-state composite polymer electrolytes (CPEs) are promising for solving the safety problem of lithium metal batteries. However, the CPEs with comparable thickness (10 μm), improved ion conductivities and excellent mechanical strength are great challenges. In the present study, ultrathin (9.6 μm), flexible, mechanically strong, and sandwiched structure solid-state electrolytes (SSEs) are fabricated by a tape casting process, involving the 75 wt % LLTO/PVDF-CPE (LLTO-75) layer designed as intermediate layer sandwiched by two 15 wt % LLTO/PVDF-CPE (LLTO-15) layers. The LLTO-15 is a soft, stable layer on upper and lower sides that could create excellent interfacial contact with electrodes, and LLTO-75 possesses physical rigidity that could inhibit the Li dendrites growth. The balancing between the excellent interfacial contact of LLTO-15 and the inhibition of lithium dendrites growth of LLTO-75 gives sandwiched SSE a high ionic conductivity (4.7 × 10-4 S cm-1) at room temperature, an excellent mechanical strength (7.2 MPa), and uniform Li plating/stripping. When coupled with LiFePO4 and Li metal, the battery assembled with sandwiched SSE maintains 91.7% of its capacity and 99.7% of the Coulombic efficiency, after 1000 cycles. Our study suggests that the proposed sandwiched structure SSE is one of the alternatives for high performance solid-state LMBs.

Integrated lithium metal anode protected by composite solid electrolyte film enables stable quasi-solid-state lithium metal batteries

Lithium (Li) metal, possessing an extremely high theoretical specific capacity (3860 mAh/g) and the most negative electrode potential (−3.040 V vs. standard hydrogen electrode), is one the most favorable anode materials for future high-energy-density batteries. However, the poor cyclability and safety issues induced by extremely unstable interfaces of traditional liquid Li metal batteries have limited their practical applications. Herein, a quasi-solid battery is constructed to offer superior interfacial stability as well as excellent interfacial contact by the incorporation of Li@composite solid electrolyte integrated electrode and a limited amount of liquid electrolyte (7.5 μL/cm2). By combining the inorganic garnet Al-doped Li6.75La3Zr1.75Ta0.25O12 (LLZO) with high mechanical strength and ionic conductivity and the organic ethylene-vinyl acetate copolymer (EVA) with good flexibility, the composite solid electrolyte film could provide sufficient ion channels, sustained interfacial contact and good mechanical stability at the anode side, which significantly alleviates the thermodynamic corrosion and safety problems induced by liquid electrolytes. This innovative and facile quasi-solid strategy is aimed to promote the intrinsic safety and stability of working Li metal anode, shedding light on the development of next-generation high-performance Li metal batteries.