Wenjia Wu

Gel electrolyte (GE) gains intensive attentions for lithium metal battery, especially those targeting to use at low temperatures. The liquid medium, as the core component, of most gel electrolytes (GEs) is organic liquid or ionic liquid, always suffering from serious safety issue and low transference number (t+). The low t + aggravates concentration polarization and thus leads to the increase of overpotential and undesirable side reactions. Herein, zwitterionic liquid (ZIL) with high stability and safety is prepared by mixing zwitterion (ZI) and lithium salt. The ZIL is then encapsulated into a SiO2 matrix to fabricate novel gel electrolyte (SiGE-ZIL). The low freezing point and strong mobility of ZIL confer SiGE-ZIL a high conductivity of 3.36 × 10−4 S cm−1 at −40 °C. Importantly, the large dipole moment of ZI effectively accelerates the dissociation of lithium salt, permitting a high t+ of 0.553 at −40 °C, which is 2.3 times of that of the …

Solid polymer electrolyte (SPE) shows great potential for all-solid-state batteries because of the inherent safety and flexibility; however, the unfavourable Li+ deposition and large thickness hamper its development and application. Herein, a laminar MXene functional layer‒thin SPE layer‒cathode integration (MXene-PEO-LFP) is designed and fabricated. The MXene functional layer formed by stacking rigid MXene nanosheets imparts higher compressive strength relative to PEO electrolyte layer. And the abundant negatively-charged groups on MXene functional layer effectively repel anions and attract cations to adjust the charge distribution behavior at electrolyte–anode interface. Furthermore, the functional layer with rich lithiophilic groups and outstanding electronic conductivity results in low Li nucleation overpotential and nucleation energy barrier. In consequence, the cell assembled with MXene-PEO-LFP …

Solid polymer electrolytes (SPEs) hold great application potential for solid-state lithium metal battery because of the excellent interfacial contact and processibility, but being hampered by the poor room-temperature conductivity (∼ 10− 7 S· cm− 1) and low lithium-ion transference number. Here, a lamellar composite solid electrolyte (Vr-NH 2@ polyvinylidene fluoride (PVDF) LCSE) with β-conformation PVDF is fabricated by confining PVDF in the interlayer channel of-NH 2 modified vermiculite lamellar framework. We demonstrate that the conformation of PVDF can be manipulated by the nanoconfinement effect and the interaction from channel wall. The presence of-NH 2 groups could induce the formation of β-conformation PVDF through electrostatic interaction, which serves as continuous and rapid lithium-ion transfer pathway. As a result, a high room-temperature ionic conductivity of 1.77× 10− 4 S· cm− 1 is …

Developing laminar composite solid electrolyte with ultrathin thickness and continuous conduction channels in vertical direction holds great promise for all‐solid‐state lithium batteries. Herein, a thin, laminar solid electrolyte is synthesized by filtrating –NH2 functionalized metal‐organic framework nanosheets and then being threaded with poly(ethylene oxide) chains induced by the hydrogen‐bonding interaction from –NH2 groups. It is demonstrated that the threaded poly(ethylene oxide) chains lock the adjacent metal‐organic framework nanosheets, giving highly enhanced structural stability (Young’s modulus, 1.3 GPa) to 7.5‐μm‐thick laminar composite solid electrolyte. Importantly, these poly(ethylene oxide) chains with stretching structure serve as continuous conduction pathways along the chains in pores. It makes the non‐conduction laminar metal‐organic framework electrolyte highly conductive: 3.97 × 10 …

In the past decades, membrane technology has been widely utilized in various separation processes, because of their low-energy consumption, low-cost, reliability, and scalability when compared with conventional separation processes like distillation, extraction, or crystallization (Sholl and Lively in Nat News 532:435–437, 2016; Yang et al. in Chem Soc Rev 49:5359–5406, 2020). In order to further increase the competitiveness, intensive efforts have been made from improving the separation efficiency of existing membrane processes to exploring new applications. As the core part, membrane materials with high permeability, high selectivity, and high stability are extremely desired since they can significantly accelerate the practical application of membrane technology.

Electrolytes that can work over a wide temperature range are crucial forsustainable advanced energy systems. Here, a kind of lamellar ionic liquid composite electrolyte (L‐ILCE) is explored through confining ionic liquids (ILs) in ordered interlayer nanochannels of 2D vermiculite framework. It is demonstrated that, within nanochannels, the finely tuned microstructure can induce the rearrangement and crystallinity of ILs, affording L‐ILCE the combined superiorities of liquid electrolyte and solid‐state electrolyte. L‐ILCE exhibits high ionic conductivities (0.09–1.35 × 10−3 S cm−1 at −40 to 100 °C), whereas polymer and inorganic electrolytes usually lose ionic conduction ability below 0 °C. Additionally, L‐ILCE exhibits high transference number (0.89, comparable with single‐ion conductors) and wide electrochemical window (0–5.3 V). LiFePO4||Li and high‐voltage LiNi0.8Mn0.1Co0.1O2||Li cells assembled from L …

The development and utilization of high-performance and high-energy–density battery is indispensable to meet the ever-increasing demands in advanced energy storage system (Bruce et al. in Nat Mater 11:19–29, 2012; Ran et al. in J Mater Chem A 6:23278–23282, 2018; Zhao et al. in Electrochim Acta 254:308–319, 2017; Yan et al. in Adv Energy Mater 9:1900148, 2019; Peng et al. in Adv Energy Mater 7:1700260, 2017). Particularly, lithium–sulfur (Li–S) battery is considered to be the most promising next-generation battery due to high theoretical capacity (1675 mAh g−1), high theoretical energy density (2600 Wh kg−1), and low cost.

As a new class of porous material, polymer-metal-organic framework (polyMOF) has attracted tremendous interests owing to their combined advantages of polymer and crystalline MOF. However, the poor film-forming ability of polyMOF limits its widespread application, especially in membrane separation area. Herein, for the first time, we demonstrate the fabrication of freestanding polyMOF membrane. The polyMOF nanosheets are synthesized by a polymer-assisted self-inhibition crystal growth strategy. Followed by self-assembly through vacuum filtration, a 20 µm-thick free-standing polyMOF membrane is constructed. Benefiting from the inclusion of polymer with hydrophobic backbone and the continuously distributed non-coordinated hydrophilic groups along polymer chain, the polyMOF membrane attains excellent structure stability against water, as well as superior proton transfer property. Proton conductivity as …

Proton exchange membrane (PEM) with ordered and stable pathway is highly desirable for use in proton exchange membrane fuel cells. Porous MOF materials hold great promise for the development of high-performance PEM due to the pre-designable and ordered pore structure, providing regular transfer channel. However, the developed water-stable MOFs usually require hydrophobic pores for stabilizing crystal structure in moisture circumstances. It leads to dramatically declined proton conductivity at low relative humidity (RH) because of severe water loss. Herein, we propose the fabrication of hydrophilic and water-stable MOF nanosheets (usCNT@CuTCPP, ∼2.8 nm) through ultrashort carbon nanotube (usCNT)-assisted self-inhibition crystal growth strategy. Then, ∼ 8.9 μm-thick usCNT@CuTCPP lamellar membrane was prepared by self-stacking of nanosheets. We demonstrate that in-situ incorporation of …

Hydrogen fuel cell, as a typical chemical-to-electrical energy conversion device, has been used in a series of applications, such as power plant, aviation, and automobile [1–4]. As the core component, the performance of PEM determines the hydrogen fuel cell efficiency. According to the proton transfer mechanism of PEM, the formation of continuous proton conduction pathways is vital to increase membrane proton conductivity [5]. However, an inherent problem for traditional polymer membranes is that, due to the complex chain structure and weak interaction, the channel structure is often unsatisfactory in connectivity and stability, especially under harsh environment, such as high temperature and low humidity [6, 7]. Incorporating nanofiller to prepare hybrid or composite membrane is considered as a facile approach to interconnect the intrinsic deadends of polymer electrolyte and construct additional pathways along …

Proton conduction is essential for proton exchange membrane (PEM) in hydrogen fuel cell. However, the proton conductivity of most PEMs is limited by the inferior continuity of transport channels and random arrangement of transfer carriers. Here, charged vermiculite lamellar membrane with orderly aligned glycine molecules in the interlayer channel is fabricated. We demonstrate that sulfonic acid-grafted channel induces and interacts with the end amino groups of glycine molecules, forming ordered acid-base pairs along the wall. Meantime, the carboxyl groups at the other end are located in the middle of channel, forming continuous hydrogen bond networks. Such molecule arrangement creates long-range hoping highways for proton conduction. The Vr-SO3H@Gly membrane (∼8 μm in thickness) with 10.2 wt% glycine obtains horizontal conductivity of 378.5 mS cm−1 at 90 °C and 100% RH, 2.2 times of that of …

Garnet-type oxide Li7La3Zr2O12 (LLZO) has attracted considerable attention as promising solid-state electrolyte (SSE) owing to the exceptional bulk ion conduction. However, the Li+ transfer capacity of most LLZO-based solid electrolytes remains inadequate, primarily due to the presence of extensive grain boundaries and excessive thickness. Herein, we report the fabrication of a LLZO-based lamellar composite inorganic solid electrolyte (LLZO/LIC LISE) by in-situ sintering Li3InCl6 (LIC) in LLZO lamellar framework. LIC can act as an effective Li+-conductive grain boundary modifier within the electrolyte, leading to a remarkable reduction in grain boundary resistance of LLZO/LIC LISE (<9.2 Ω cm2), which is much lower than that of LLZO lamellar framework (827.2 Ω cm2). Together with the reduced internal grain boundary of LLZO nanosheet, a high ionic conductivity of 3.22 × 10−4 S cm−1 at 25 °C is obtained for …

This book provides an overview of functional membranes for efficient ion/molecule transfer and separation. It first presents the design, fabrication, structure, and performance of several kinds of membranes. Then, the application of membrane technology in organic solvent nanofiltration, hydrogen fuel cells, and solid-state lithium batteries is introduced. Furthermore, the book proposes strategies of strengthening the ion/molecular-level separation and transfer process in membrane processes. It also analyzes the development status, existing problems, and optimization methods in the field of membranes and membrane processes. Finally, it highlights the construction strategy of membrane structures, the structure–performance relationships as well as the transfer and separation mechanisms. The target group of this book is academics and researchers in materials science, chemical engineering, biomedical engineering, and other related fields.

Inorganic superionic conductors hold great promise for all-solid-state lithium battery. However, the ionic conductivity of developed inorganic solid electrolytes (ISEs) is often insufficient owing to the enormous grain boundary resistance and large thickness. Herein, a 30 μm-thick Li7La3Zr2O12 (LLZO) lamellar inorganic solid electrolyte (LLZO/CN LISE) is fabricated by assembling LLZO nanosheets into lamellar framework, followed by in-situ growing g-C3N4 in the interlayer spacing. Based on the regular and unambiguous lamellar structure, g-C3N4 is found to be an ideal grain boundary modifier, and the Li-ion transfer process at grain boundary is thus investigated in detail. We demonstrate that this LLZO/CN LISE achieves an ultralow grain boundary resistance (<12.3 Ω cm2 vs. 1608 Ω cm2 for LLZO pellet) and hence high ionic conduction properties (the ionic conductivity is 2.50 × 10−4 S cm−1 and the ionic …

The two-dimensional covalent organic framework (COF) with continuous and stable pores as well as tunable functional groups is considered as promising proton exchange membrane (PEM) material. However, due to the strong rigidity and inferior processability of COFs, it still remains challenging to prepare a self-standing and robust membrane. Herein, self-standing and robust thin COF membranes (20 μm in thickness) were fabricated through the in situ involvement of hyperbranched polyethylenimine (HPEI). The HPEI cross-links the adjacent COF particles and enhances the interactions among them. The involvement of HPEI enables polyCOM to have excellent structure ability, mechanical property, and proton conduction ability. As a result, poly0.2COM obtains a high water uptake of 72.3% at 80 °C (vs 49.11% for Nafion) with a negligible swelling ratio of 1.5%. In addition, the tensile strength of poly0.2COM …

Succinonitrile (SN) plastic crystal electrolyte holds great promise for high-performance solid-state lithium metal batteries due to its high ionic conduction. However, the serious side reaction between SN and lithium anode always causes large interfacial resistance, deteriorating the battery capacity. Herein, we penetrated LiTFSI-SN (LSN) electrolyte into the interlayer channels of laminar metal-organic framework (MOF), then an ultra-thin and stable laminar LiTFSI–SN–MOF composite solid-state electrolyte (LSN-MOF CSE) was obtained. We demonstrate that the interlayer nanochannels for LSN electrolyte storage without sacrificing the mobility of SN molecules. Meanwhile, the unsaturated coordination of MOF, induced by Co/Ni metal sites, causes a horizontal arrangement of SN. Therefore, this electrolyte offers a remarkable ionic conductivity of 7.41 × 10−4 S cm−1 at 25 °C. Moreover, the interlayer nanochannels and …

One scalable and facile dip-coating approach was utilized to construct a thin CO2-selection layer of Pebax/PEGDA-MXene on a hollow fiber PVDF substrate. An interlayer spacing of 3.59 Å was rationally designed and precisely controlled for the MXene stacks in the coated layer, allowing efficient separation of the CO2 (3.3 Å) from N2 (3.6 Å) and CH4 (3.8 Å). In addition, CO2-philic nanodomains in the separation layer were constructed by grafting PEGDA into MXene interlayers, which enhanced the CO2 affinity through the MXene interlayers, while non-CO2-philic nanodomains could promote CO2 transport due to the low resistance. The membrane could exhibit optimal separation performance with a CO2 permeance of 765.5 GPU, a CO2/N2 selectivity of 54.5, and a CO2/CH4 selectivity of 66.2, overcoming the 2008 Robeson upper bounds limitation. Overall, this facile approach endows a precise controlled …

The development of a high-performance electrolyte that can work at low temperatures is critical for expanding the application of lithium metal batteries. However, most of the present electrolytes suffer from low ionic conductivity and poor interface contact at low temperatures. Herein, an ∼21 μm-thick quasi-solid polymer electrolyte is prepared by in situ polymerization of 1,3-dioxlane (PDOL) within the poly(vinyl alcohol)/polyethylenimine (PVA/PEI) nanofiber skeleton that contains −NH– groups. The generated hydrogen bond interactions between PDOL and PVA/PEI nanofiber, together with the inherently strong mechanical strength of the nanofiber, confer quasi-solid polymer electrolyte (QSE@PVA/PEI) the tensile strength of 12.1 MPa. Meanwhile, the interactions also interfere with the chain arrangement of PDOL and efficiently enhance the chain mobility, giving QSE@PVA/PEI a remarkable ionic conductivity of 3.29 …

Two‐dimensional lamellar membranes are promising for efficient molecule transfer, while the underlying transfer mechanism is rarely elucidated. Herein, heterostructured nanosheets are prepared by self‐assembling small‐sized hydrophilic cyanuric acid melamine and hydrophobic g‐C3N4 nanosheets. Resultant lamellar membranes show comparable affinity to polar and nonpolar solvents, allowing them to dissolve on membrane surface and diffuse through membrane channels. Results demonstrate that for lamellar membranes with distinct wettability, the permeance difference for polar solvents is originated from dissolution and diffusion processes, while that for nonpolar solvents is stemmed from dissolution process. Accordingly, corresponding equations which are suitable for heterostructured lamellar membranes are established. Importantly, polar solvents are induced to form ordered arrangement in …

Hydrogen-bonded organic frameworks (HOFs) with continuous hydrogen bond networks, programmable pore structure and functional sites, are promising next-generation functional membrane materials. Here, we demonstrate the fabrication of a free-standing HOF membrane for the first time, and explore the proton conduction performance. Concretely, HOF membrane was prepared by assembling HOF precursors into nanosheets, followed by vacuum filtration and annealing treatment. We confirm that the annealing treatment exerts significant influence on membrane topology, which allows the construction of efficient vertical conduction pathways. The vertical conductivity of HOF membrane reaches 59.8 mS cm−1 at 90 °C and 100% relative humidity (RH), with low conduction anisotropy of 4.4, which are superior to most organic framework membranes. The maximum current density and power density of assemble …