Multifunctional Interlayer Research Articles

Conductive nanofabrics as multifunctional interlayer of sulfur-loading cathode towards durable lithium-sulfur batteries

Conductive nanofabrics as multifunctional interlayer of sulfur-loading cathode towards durable lithium-sulfur batteries

Multifunctional Interlayer Including Metal Fluoride–Modified PAN/PSF–Based Superfine and Porous Carbon Nanofibers for Stable Lithium Metal Cells

Multifunctional Interlayer Including Metal Fluoride–Modified PAN/PSF–Based Superfine and Porous Carbon Nanofibers for Stable Lithium Metal Cells

A multifunctional interlayer between mesoporous TiO2 and perovskite for perovskite solar cells with high efficiency and stability

The industrialization of the perovskite solar cells (PSCs) requires further lifting their power conversion efficiency (PCE). There are some important factors to hinder the PCE improvement, such as interface defects and energy level mismatching betwee electron transport layer (ETL) and perovskite layer, and solar energy loss due to no absorption of near infrared (NIR) for the perovsktie. Thus in this study, a multifunctional material of W-Er-Yb doped TiO2 (W-UC-TiO2) was prepared and applied to PSCs as an interlayer between mesoporous TiO2 and perovskite. The experimental results demonstrate that the interlayer of W-UC-TiO2 has the functions of improving NIR absorption for PSCs, passivating inerface defects and improving energy level matching between TiO2 and perovskite. A high efficiency of 21.32% was acquired for the PSCs with W-UC-TiO2 interlayer from 19.26% for the control device. Moreover, stability of the PSCs was improved by the insertion of W-UC-TiO2 interlayer.

Nitrogen-Doped TiO2- x(B)/MXene Heterostructures for Expediting Sulfur Redox Kinetics and Suppressing Lithium Dendrites.

Practical application of lithium-sulfur (Li-S) batteries is severely impeded by the random shuttling of soluble lithium polysulfides (LiPSs), sluggish sulfur redox kinetics, and uncontrollable growth of lithium dendrites, particularly under high sulfur loading and lean electrolyte conditions. Here, nitrogen-doped bronze-phase TiO2(B) nanosheets with oxygen vacancies (OVs) grown in situ on MXenes layers (N-TiO2- x(B)-MXenes) as multifunctional interlayers are designed. The N-TiO2- x(B)-MXenes show reduced bandgap of 1.10eV and high LiPSs adsorption-conversion-nucleation-decomposition efficiency, leading to remarkably enhanced sulfur redox kinetics. Moreover, they also have lithiophilic nature that can effectively suppress dendrites growth. The cell based on the N-TiO2- x(B)-MXenes interlayer under sulfur loading of 2.5mg cm-2 delivers superior cycling performance with a high specific capacity of 690.7 mAh g-1 over 600 cycles at 1.0 C. It still has a notable areal capacity of 6.15 mAh cm-2 after 50 cycles even under a high sulfur loading of 7.2mg cm-2 and a low electrolyte-to-sulfur (E/S) ratio of 6.4 µL mg-1. The Li-symmetrical battery with the N-TiO2- x(B)-MXenes interlayer showcases a low over-potential fluctuation with 21.0mV throughout continuous lithium plating/stripping for 1000h. This work offers valuable insights into the manipulation of defects and heterostructures to achieve high-energy Li-S batteries.

Reusable multifunctional interlayer for dendrite-free and ultrastable zinc anodes via regulating zinc-ion transport and inhibiting hydrogen evolution

The practical application of zinc anodes in aqueous zinc-ion batteries (ZIBs) is hindered due to uncontrollable dendritic Zn deposition and side reactions. Herein, a reusable interlayer constructed from Sn nanoparticles-modified polyhydroxy semi-carbonized bacterial cellulose (Sn@PHCBC) with three-dimensional interconnected network structure is proposed to achieve sustainable and smooth regulation of zinc anode. The suppression of dendrites is primarily attributed to the uniform Zn ions flux constructed by reversible Sn-Zn alloy nanoparticles channel, as well as the targeted transport and rapid desolvation of hydrated zinc ions through hydroxyl groups of PHCBC. Additionally, the abundant high overpotential Sn nanoparticles anchored in Sn@PHCBC interlayer effectively inhibit the hydrogen evolution reaction and minimize the formation of byproducts. As a result, the Zn||Zn symmetrical cell assembled with Sn@PHCBC interlayer demonstrates highly reversible electroplating/stripping behavior with an extended lifespan of 800 h at high current densities of 10 mA cm−2 and 10 mAh cm−2. Besides, after 1000 cycles of MnO2||Sn@PHCBC//Zn full cell, the Sn@PHCBC interlayer can still be reused with nearly 100 % coulombic efficiency after simple treatment. The rational design in this work provides a feasible solution for high-performance ZIBs and promote the development of advanced energy storage devices reutilization.

In Situ Constructing a TiO2/TiN Heterostructure Modified Carbon Interlayer for Balancing the Surface Adsorption and Conversion of Polysulfides in Li–S Batteries

AbstractSevere shuttle effect and sluggish reaction kinetics caused by lithium‐polysulfides have always been the dominant factor to reduce the actual energy density of lithium–sulfur batteries. It's very important to simultaneously balance the surface adsorption and redox conversion of the lithium‐polysulfides. Herein, a TiO2/TiN heterostructure and in situ N‐doping modified multifunctional carbon interlayer is designed and constructed using a melamine foam as the matrix material at a relatively low temperature and without NH3 atmosphere. Interestingly, TiO2 nano‐particles decorated on the N‐enriched melamine carbon foam can be partially in situ transformed into TiN during pyrolysis process. Based on the support of highly conductive and interconnected carbon skeletons, the N heteroatom and TiO2/TiN show good synergetic adsorption and conversion of the soluble lithium‐polysulfides, whilst boosting the electrochemical performance of lithium–sulfur batteries. Consequently, when used the multifunctional carbon interlayer, the Super P/sulfur cathode based lithium–sulfur battery delivers a high initial discharge capacity of 814 mAh g−1 at a high current rate of 2.0 C and maintain the 548 mAh g−1 after 500 cycles. Even with the high sulfur loading of 7.5 mg cm−2 and low E/S ratio of 4.7 µL mg−1, an acceptable areal capacity of 8.2 mAh cm−2 can be obtained.

Co–Ni bimetallic selenides embedded in honeycomb carbon framework as multifunctional separator interlayer to enhance the electrochemical performance of Li–S batteries

The commercialization of Li–S batteries is severely hampered by the electrically insulated nature of S and the discharge product Li2S, the shuttle effect of lithium polysulfides (LiPSs), and the slow redox kinetics between Li2S2/Li2S. Herein, a composite of Co–Ni bimetallic selenide nanoparticles embedded in honeycomb porous carbon (Co–Ni–Se@C) is prepared and used as a multifunctional interlayer on the separator to solve the above-mentioned challenges in Li–S batteries. The Co–Ni–Se@C composite with high electrical conductivity can not only accelerate Li+ and electronic transfer but also have good chemisorption and catalytic activity for LiPSs, which can maximize the utilization of sulfur active material. As expected, Li–S batteries assembled with Co–Ni–Se@C-PP separator exhibit excellent electrochemical performance, including high initial discharge capacity of 1245 mAh g−1 at 0.2 C, superior long cycling stability with a 0.066 % decay per cycle at 1.0 C, and an excellent rate capacity of 674 mAh g−1 at 5.0 C. In addition, a satisfactory capacity of 1174 mAh g−1 is achieved with a high sulfur loading of 3.7 mAh g−1 and a low E/S ratio of 10 μL mg−1. This work provides a new insight into the application of bimetallic selenides in high-performance Li–S batteries.

Encasing Few-Layer MoS2 within 2D Ordered Cubic Graphitic Cages to Smooth Trapping-Conversion of Lithium Polysulfides for Dendrite-Free Lithium-Sulfur Batteries.

The industrialization of lithium-sulfur (Li-S) batteries faces challenges due to the shuttling effect of lithium polysulfides (LiPSs) and the growth of lithium dendrites. To address these issues, a simple and scalable method is proposed to synthesize 2D membranes comprising a single layer of cubic graphitic cages encased with few-layer, curved MoS2. The distinctive 2D architecture is achieved by confining the epitaxial growth of MoS2 within the open cages of a 2D-ordered mesoporous graphitic framework (MGF), resulting in MoS2@MGF heterostructures with abundant sulfur vacancies. The experimental and theoretical studies establish that these MoS2@MGF membranes can act as a multifunctional interlayer in Li-S batteries to boost their comprehensive performance. The inclusion of the MoS2@MGF interlayer facilitates the trapping and conversion kinetics of LiPSs, preventing their shuttling effect, while simultaneously promoting uniform lithium deposition to inhibit dendrite growth. As a result, Li-S batteries with the MoS2@MGF interlayer exhibit high electrochemical performance even under high sulfur loading and lean electrolyte conditions. This work highlights the potential of designing advanced MoS2-encased heterostructures as interlayers, offering a viable solution to the current limitations plaguing Li-S batteries.

A Crystalline 2D Fullerene‐Based Metal Halide Semiconductor for Efficient and Stable Ideal‐bandgap Perovskite Solar Cells

AbstractDespite advances in mixed tin‐lead (Sn‐Pb) perovskite‐based solar cells, achieving both high‐efficiency and long‐term device stability remains a major challenge. Current device deficiencies stem partly from inefficient carrier transport, originating from defects and improper band energy alignment among the device's interfaces. Developing multifunctional interlayer materials simultaneously addressing the above concerns poses an excellent strategy. Herein, through molecular and crystal engineering, an amine‐functionalized C60 mono‐adduct derivative (C60‐2NH3 = bis(2‐aminoethyl) malonate‐C60) is utilized for the synthesis of the first crystalline fullerene‐based 2D metal halide semiconductor, namely (C60‐2NH3)Pb2I6. Single crystal XRD studies elucidated the structure of the new material, while DFT calculations highlighted the strong contribution of C60‐2NH3 to the electronic density of states of the conduction band of (C60‐2NH3)Pb2I6. Utilization of C60‐2NH3 as an interlayer between a FA0.6MA0.4Pb0.7Sn0.3I3 perovskite and a C60 layer offered superior band energy alignment, reduced nonradiative recombination, and enhanced carrier mobility. The corresponding perovskite solar cell (PSC) device achieved a power conversion efficiency (PCE) value of 21.64%, maintaining 90% of its initial efficiency, after being stored under a N2 atmosphere for 2400 h. This work sets the foundation for developing a new family of functional materials, namely Fullerene Metal Halide Semiconductors, targeting applications from photovoltaics to catalysis, transistors, and supercapacitors.

Synergistic Stabilization of Zn Metal Anodes by 3D Carbon Frameworks with Multiple Ion Channels Loaded with Zincophilic BaTiO3 Nanoparticles

Aqueous zinc‐ion batteries (AZIBs) suffer from rampant Zn dendrites growth, corrosion and sluggish transport kinetics, all of which have a serious impact on their performance and practical applications. Therefore, porous carbon nanofibers (BTO@PCNFs) loaded with BaTiO3 nanoparticles (BTO NPs) are constructed as a multifunctional interlayer for stabilizing the Zn anodes. Owing to the synergistic effect of BTO NPs and 3D porous carbon framework, this interlayer can achieve uniform electric field distribution, accelerate Zn2+ migration, and promote ion flux homogenization, thus leading to uniform Zn deposition. Meanwhile, the BTO@PCNFs interlayer demonstrates excellent anti‐corrosion effect, which can effectively prevent the side reactions. Benefiting from the synergistic effect of interlayers, the BTO@PCNFs multifunctional interlayers achieve a comprehensive optimization of the Zn anodes. The BTO@PCNFs‐Zn electrode exhibits lower nucleation overpotential (33.5 mV) at 0.5 mA cm−2. The Zn//Zn symmetrical cell with BTO@PCNFs interlayer exhibits ultra‐low overpotential (14 mV) and ultra‐long cycle life (5250 h at 0.5 mA cm−2). Even at high current density (30 mA cm−2), the BTO@PCNFs‐Zn electrode can be stably cycled for more than 830 h, achieving an ultra‐high cumulative capacity of 12 450 mAh cm−2. The multifunctional interlayers can provide a reference for the design of high‐performance Zn anodes.

2D Ultrathin Titanium Nitride Nanosheets as Separator Coatings for Li-S Batteries.

Transition metal nitrides (TMNs) are affirmed to be an appealing candidate for boosting the performance of lithium-sulfur (Li-S) batteries due to their excellent conductivity, strong interaction with sulfur species, and the effective catalytic ability for conversion of polysulfides. However, the traditional bulk TMNs are difficult to achieve large active surface area and fast transport channels for electrons/ions simultaneously. Here, a 2D ultrathin geometry of titanium nitride (TiN) is realized by a facile topochemical conversion strategy, which can not only serve as an interconnected conductive platform but also expose abundant catalytic active sites. The ultrathin TiN nanosheets are coated on a commercial separator, serving as a multifunctional interlayer in Li-S batteries for hindering the polysulfide shuttle effect by strong capture and fast conversion of polysulfides, achieving a high initial capacity of 1357mAhg-1 at 0.1C and demonstrating a low capacity decay of only 0.046% per cycle over 1000 cycles at 1C.

Tuning the crystallinity of titanium nitride on copper‐embedded carbon nanofiber interlayers for accelerated electrochemical kinetics in lithium–sulfur batteries

AbstractThe development of lithium–sulfur (Li–S) batteries is hindered by the disadvantages of shuttling of polysulfides and the sluggish redox kinetics of the conversion of sulfur species during discharge and charge. Herein, the crystallinities of a titanium nitride (TiN) film on copper‐embedded carbon nanofibers (Cu‐CNFs) are regulated and the nanofibers are used as interlayers to resolve the aforementioned crucial issues. A low‐crystalline TiN‐coated Cu‐CNF (L‐TiN‐Cu‐CNF) interlayer is compared with its highly crystalline counterpart (H‐TiN‐Cu‐CNFs). It is demonstrated that the L‐TiN coating not only strengthens the chemical adsorption toward polysulfides but also greatly accelerates the electrochemical conversion of polysulfides. Due to robust carbon frameworks and enhanced kinetics, impressive high‐rate performance at 2 C (913 mAh g−1 based on sulfur) as well as remarkable cyclic stability up to 300 cycles (626 mAh g−1) with capacity retention of 46.5% is realized for L‐TiN‐Cu‐CNF interlayer‐configured Li–S batteries. Even under high loading (3.8 mg cm−2) of sulfur and relatively lean electrolyte (10 μL electrolyte per milligram sulfur) conditions, the Li–S battery equipped with L‐TiN‐Cu‐CNF interlayers delivers a high capacity of 1144 mAh g−1 with cathodic capacity of 4.25 mAh cm−2 at 0.1 C, providing a potential pathway toward the design of multifunctional interlayers for highly efficient Li–S batteries.

A multifunctional self-supporting LLTO/C interlayer for high-performance lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries are recognized as an encouraging alternative for future power storage technologies. However, their practical application is hindered by several significant challenges, including slow redox kinetics, the shuttle effect, and the formation of lithium dendrites. Here a binder-free, self-supporting multifunctional interlayer composed of lithium lanthanum titanate (LLTO) with amorphous carbon nanofiber matrices for Li-S batteries has been constructed. This multifunctional interlayer has been designed to facilitate the redox kinetics of lithium polysulfides (LiPSs), promote the nucleation of lithium sulfide (Li2S), and hinder the formation of lithium dendrites. The electrocatalytic properties of the interlayer were subjected to systematic evaluation through electrochemical testing, and the lithium deposition was assessed by examining the surface evolution of lithium metal in symmetric cells. The LLTO carbon matrix interlayer sustained a high specific capacity of 703.3 mA h g-1 after 200 cycles at 0.1C, with a sulfur loading of 5.5 mg cm-2. Furthermore, it demonstrated a high capacity of 905.9 mA h g-1 with a decay rate of 0.069% per cycle over 1000 cycles at a current density of 5C with a sulfur loading of 1 mg cm-2. This investigation highlights the potential of LLTO carbon composite materials as multifunctional interlayers, which could facilitate the optimization of advanced Li-S batteries.

The construction of multifunctional solid electrolyte interlayers for stabilizing Li6PS5Cl-based all-solid-state lithium metal batteries

The established multifunctional interlayers effectively eliminate both anode-initiated and GB-initiated dendrites and guarantee satisfactory battery performance for ASSLMBs.

Facile preparation of a lightweight multifunctional interlayer for high-performance Li-S batteries.

The construction of functional interlayers for separator modification in Li-S batteries has been proven to be a feasible and effective strategy to alleviate the shuttle effect. However, several challenging issues in interlayer design and fabrication, including the tedious material preparation process and high weight loading of the interlayer on the pristine separator, jeopardize the battery energy density. In this work, a nitrogen-abundant nanoporous carbon/graphene (NC/G) composite was synthesized by a facile method and fabricated into a lightweight membrane, which was investigated as a multifunctional interlayer in a Li-S battery. The abundant nitrogen sites and nanoporous structure of NC/G can effectively anchor and trap polysulfides; graphene (G) can create an excellent conductive network in NC/G. These attributes of NC/G are able to efficiently boost the sulfur redox reaction kinetics and significantly suppress the shuttle effect, leading to superb battery performance. More importantly, the low density of NC/G was conducive to reducing the load on the separator, thus reducing the decline in battery energy density, which is promising for practical applications. Even at an ultra-low loading of NC/G on the pristine separator (0.08 mg cm-2), the battery showed a competitive electrochemical performance compared with many reported materials. We believe this work provides a strategic guidance for the future fabrication of promising functional interlayers for practical Li-S battery applications.

A Freestanding Multifunctional Interlayer Based on Fe/Zn Single Atoms Implanted on a Carbon Nanofiber Membrane for High-Performance Li-S Batteries

By virtue of the high theoretical energy density and low cost, Lithium–sulfur (Li-S) batteries have drawn widespread attention. However, their electrochemical performances are seriously plagued by the shuttling of intermediate polysulfides and the slow reaction kinetics during practical implementation. Herein, we designed a freestanding flexible membrane composed of nitrogen-doped porous carbon nanofibers anchoring iron and zinc single atoms (FeZn-PCNF), to serve as the polysulfide barrier and the reaction promotor. The flexible porous networks formed by the interwoven carbon nanofibers not only offer fast channels for the transport of electrons/ions, but also guarantee the structural stability of the all-in-one multifunctional interlayer during cycling. Highly dispersed Fe and Zn atoms in the carbon scaffold synergistically immobilize sulfur species and expedite their reversible conversion. Therefore, employing FeZn-PCNF as the freestanding interlayer between the cathode and separator, the Li-S battery delivers a superior initial reversible discharge capacity of 1140 mA h g−1 at a current density of 0.5 C and retains a high capacity of 618 mA h g−1 after 600 cycles at a high current density of 1 C.

Constructing Ag@SiO2-TiO2 Nanofiber Interlayers with a Three-Dimensional Lithiophilic Gradient Framework for an Ultrastable Lithium Metal Anode.

Lithium metal batteries have become one of the most promising rechargeable batteries due to the ultrahigh theoretical specific capacity of the Li metal anode. However, the Li dendrite growth and volume change of the Li metal anode during repeated Li plating-stripping cycles restrict the practical viability. Herein, a unique lithiophilic gradient structure of uniformly incorporating Ag nanoparticles into a three-dimensional (3D) nanofiber framework with amorphous SiO2 and TiO2 hybrids was prepared by an electrospinning process and used as a multifunctional interlayer between the pristine separator and Li metal foil. The 3D framework not only possesses excellent flexibility but also alleviates volume changes, which can withstand massive Li loading and promote uniform Li+ distribution. In addition, the 3D lithiophilic gradient structure allows for regulable Li+ flux and suppresses Li dendrite growth. Impressively, the Li||Li symmetric batteries with Ag@SiO2-TiO2 interlayers exhibit a prolonged lifespan of 1500 h at 0.5 mA cm-2 for 0.5 mAh cm-2. The full cells coupled with the Ag@SiO2-TiO2 interlayer show a capacity retention rate of 94.6% after 1000 cycles and a high rate capability. This work provides promising guidance for the design of a gradient-distributed lithiophilic structure toward an ultrastable Li metal anode.

Ultrathin Mixed Ionic-Electronic Conducting Interlayer via the Solution Shearing Technique for High-Performance Lithium-Sulfur Batteries.

The commercialization of lithium-sulfur (Li-S) batteries has been hampered by diverse challenges, including the shuttle phenomenon and low electrical/ionic conductivity of lithium sulfide and sulfur. To address these issues, extensive research has been devoted to developing multifunctional interlayers. However, interlayers capable of simultaneously suppressing the polysulfide (PS) shuttle and ensuring stable electrical and ionic conductivity are relatively uncommon. Moreover, the use of thick and heavy interlayers results in an unavoidable decline in the energy density of Li-S batteries. We developed an ultrathin (750 nm), lightweight (0.182 mg cm-2) interlayer that facilitates mixed ionic-electronic conduction using the solution shearing technique. The interlayer, composed of carbon nanotube (CNT)/Nafion/poly-3,4-ethylenedioxythiophene:tetracyanoborate (PEDOT:TCB), effectively suppresses the shuttle phenomenon through the synergistic segregation and adsorption effects on PSs by Nafion and CNT/PEDOT, respectively. Furthermore, the electrical/ionic conductivity of the interlayer can be improved via counterion exchange and homogeneous Li+ ion flux/good wettability from SO3- functional group of Nafion, respectively. Enhanced sulfur utilization and reaction kinetics through polysulfide shuttle inhibition and facilitated electron/ion transfer by interlayer enable a high discharge capacity of 1029 mA h g-1 in the Li-S pouch cell under a high sulfur loading of 5.3 mg cm-2 and low electrolyte/sulfur ratio of 5 μL mg-1.

Ultra-Dispersed α-MoC1-x Embedded in a Plum-Like N-Doped Carbon Framework as a Synergistic Adsorption-Electrocatalysis Interlayer for High-Performance Li-S Batteries.

The shuttle effect and sluggish redox kinetics of lithium polysulfides (LiPSs) severely hinder the scalable application of lithium-sulfurr (Li-S) batteries. Herein, the highly dispersed α-phase molybdenum carbide nano-crystallites embedded in a porous nitrogen-doped carbon framework (α-MoC1-x @NCF) are developed via a simple metal-organic frameworks (MOFs) assisted strategy and proposed as the multifunctional separator interlayer for Li-S batteries. The inlaid MoC1-x nanocrystals and in situ doped nitrogen atoms provide a strong chemisorption and outstanding electrocatalytic conversion toward LiPSs, whereas the unique plum-like carbon framework with hierarchical porosity enables fast electron/Li+ transfer and can physically suppress LiPSs shuttling. Benefiting from the synergistic trapping-catalyzing effect of the MoC1-x @NCF interlayer toward LiPSs, the assembled Li-S battery achieves high discharge capacities (1588.1mAhg-1 at 0.1C), impressive rate capability (655.8mAhg-1 at 4.0C) and ultra-stable lifespan (a low capacity decay of 0.059% per cycle over 650 cycles at 1.0C). Even at an elevated sulfur loading (6.0mgcm-2 ) and lean electrolyte (E/S is ≈5.8µLmg-1 ), the battery can still achieve a superb areal capacity of 5.2mAhcm-2 . This work affords an effective design strategy for the construction of muti-functional interlayer in advanced Li-S batteries.

N-Doped Graphene Nanofibers with Porous Channel Comprising Fe x S y Nanocrystals and Intertwined N-Doped CNTs as Efficient Interlayers for Li-S Batteries

Hierarchically porous and conductive nanofibers (NFs) comprising nitrogen-doped reduced graphene oxide (N-rGO) and iron sulfide (Fe x S y ) nanocrystals along with highly intertwined nitrogen-doped carbon nanotubes (N-CNTs) abbreviated as “P-rGO@Fe x S y /N-CNT NFs” were synthesized via electrospinning technique as multifunctional interlayers via coating on the commercial separator for stable lithium-sulfur (Li-S) batteries. The porous N-rGO framework acts as a backbone to enhance the structural integrity of the nanostructure. The N-CNTs and N-rGO guarantee various conductive channels for quick electron transfer thus allowing fast redox reactions. The thermal breakdown of polystyrene (PS) resulted in the formation of continuous longitudinal channels. Correspondingly, the Li-S cell incorporating the P-rGO@Fe x S y /N-CNT NF-modified separator and S electrode (2.41 mg cm-2) exhibited boosted electrochemical properties such as justifiable rate capability and steady cycling performance (after 800 charge-discharge, cell exhibits a capacity of 464 mA h g-1 with 44% retention at 0.1 C). The novel synthesis strategy discussed herein will provide significant intuitions to the advancement of innovative nanostructures for different rechargeable purposes.