Multi-duties for one post: Biodegradable bacterial cellulose-based separator for lithium sulfur batteries

Revealing structure-performance relationship of biomimetic cyclodextrin metal-organic framework composite electrolytes for dendrite-free lithium metal batteries

Cyclodextrin metal-organic frameworks (CD-MOFs) with infinitely extensible network structures show potential applications in lithium metal batteries. However, the disordered accumulation of CD-MOF particles leads to slow interparticle diffusion of ions, so the CD-MOF composite electrolytes are needed to be developed. In addition, the influences of CD-MOFs structure on the electrochemical performance of the composite electrolytes remains unclear. Herein, a series of CD-MOF composite electrolytes (BCDM-X) were prepared via in-situ growth of various CD-MOFs on bacterial cellulose (BC) fibers to research the structure-performance relationship of the CD-MOF composite electrolytes. The difference in host-guest interactions and the solvation structures of the BCDM-X were confirmed by FTIR, Raman spectroscopes and theoretical calculations. It is demonstrated that the BCDM-1 electrolyte with an open multilevel hierarchical pore structure and a moderate pore size 1 to 2 times the size of anion profits for ion-sieving and regulation of solvation structure as the beat one. Therefore, the BCDM-1 electrolyte achieves high lithium-ion transference number (0.82), good ionic conductivity (1.61 mS cm-1), wide electrochemical stability window (5.1 V), and stable long-term Li plating/stripping cycling over 1500 h at 0.2 mA cm-2. By realizing homogeneous Li+ flux, the BCDM-1 composite electrolyte can inhibit the growth of lithium dendrites on the Li metal anode, prevent electrolyte decomposition, and facilitate the formation of a durable LiF-rich SEI layer. Thus, this work provides understanding of the structure-performance relationship of CD-MOF composite electrolytes for dendrite-free and high-performance LMBs.

Calcium Alginate Fibers/Boron Nitride Composite Lithium-Ion Battery Separators with Excellent Thermal Stability and Cycling Performance

As one of the most critical components in lithium-ion batteries (LIBs), commercial polyolefin separators suffer from drawbacks such as poor thermal stability and the inability to inhibit the growth of dendrites, which seriously threaten the safety of LIBs. In this study, we prepared calcium alginate fiber/boron nitride-compliant separators (CA@BN) through paper-making technology and the surface coating method using calcium alginate fiber and boron nitride. The CA@BN had favorable electrolyte wettability, flame retardancy, and thermal dimensional stability of the biomass fiber separator. Meanwhile, the boron nitride coating provided excellent thermal conductivity and mechanical strength for the composite separator, which inhibited the growth of lithium dendrites and enabled lithium-ion symmetric batteries to achieve more than 1000 stable and long cycles at a current density of 0.5 mA cm-2. The interwoven fiber mesh formed by the boron nitride coating and the calcium alginate provided multiple pathways for ion migration, which enhanced the storage capacity of the electrolyte, improved the interfacial compatibility between the separator and the electrode, widened the window of electrochemical stability, and enhanced ionic migration. This eco-friendly bio-based separator paves a new insight for the design of heat-resistance separators as well as the safe running of LIBs.

Bacterial Cellulose Applications in Electrochemical Energy Storage Devices

Bacterial cellulose (BC) is produced via the fermentation of various microorganisms. It has an interconnected 3D porous network structure, strong water-locking ability, high mechanical strength, chemical stability, anti-shrinkage properties, renewability, biodegradability, and a low cost. BC-based materials and their derivatives have been utilized to fabricate advanced functional materials for electrochemical energy storage devices and flexible electronics. This review summarizes recent progress in the development of BC-related functional materials for electrochemical energy storage devices. The origin, components, and microstructure of BC are discussed, followed by the advantages of using BC in energy storage applications. Then, BC-related material design strategies in terms of solid electrolytes, binders, and separators, as well as BC-derived carbon nanofibers for electroactive materials are discussed. Finally, a short conclusion and outlook regarding current challenges and future research opportunities related to BC-based advanced functional materials for next-generation energy storage devices suggestions are proposed.

Bacterial cellulose materials in sustainable energy devices: A review

This article provides a comprehensive review of the processing and applications of bacterial cellulose (BC) for energy conversion and storage devices. These emerging technologies enable the transformation of sustainable energy sources into electricity. Once converted, energy storage devices are vital for stable energy supply. To promote green manufacturing practices in this field, bio-based materials are explored as alternative materials for energy devices, addressing the growing demand for sustainable solutions. From a research and development perspective, the materials chosen for energy devices must exhibit exceptional mechanical, electrical, and thermal properties, along with the necessary chemical reactivity to unlock new applications. Furthermore, for successful commercialization and industrialization, these materials must be suitable for large-scale production within practical timeframes. BC fulfills all of these requirements. The review begins with an overview of BC growth, detailing the composition and operating parameters of the culture medium and the design of bioreactors for large-scale production. It then defines and summarizes both in-situ and ex-situ modifications and processing strategies, offering a comprehensive perspective on these techniques. Unique and interesting properties linking BC's structure to its properties are reviewed to demonstrate its potential as a substitute for benchmark materials. The exceptional performance and synergistic effects of BC-derived hybrid materials highlight their potential for state-of-the-art applications in energy devices, and are suitable for the next-generation energy devices. The papers reviewed in this work have gained significant attention and been widely cited over the past 10 years for their relevance to various practical applications, allowing readers to have a better understanding in development of BC based materials for energy conversion and conversion devices.

Mo3P/Mo heterojunction for efficient conversion of lithium polysulfides in high-performance lithium-sulfur batteries

Realizing efficient immobilization of lithium polysulfides (LiPSs) as well as reversible catalytic conversion between LiPSs and the insoluble Li2S is vital to restrain the shuttle effect, which requires highly reactive catalysts for high-performance Li-S batteries. Here, three-dimensional ordered porous Mo-based metal phosphides (3DOP Mo3P/Mo) with heterogeneous structures were fabricated and utilized as separator-modified coatings for Li-S batteries to catalyze the conversion of LiPSs. The adsorption, catalytic and electrochemical performance of the corresponding cells were compared among 3DOP Mo3P/Mo and 3DOP Mo, by kinetic and electrochemical performance measurements. It was found that the cell with 3DOP Mo3P/Mo modified separator deliver better electrochemical performance, with a high specific capacity of 469.66 mAh g-1 after 500 cycles at a high current density of 1°C. This work provides an idea and a guideline for the design of the separator modification for high-performance Li-S batteries.

Advanced Separator Materials for Enhanced Electrochemical Performance of Lithium-Sulfur Batteries: Progress and Prospects

Lithium-sulfur (Li-S) batteries are promising energy storage devices owing to their high theoretical specific capacity and energy density. However, several challenges, including volume expansion, slow reaction kinetics, polysulfide shuttle effect and lithium dendrite formation, hinder their commercialization. Separators are a key component of Li-S batteries. Traditional separators, made of polypropylene and polyethylene, have certain limitations that should be addressed. Therefore, this review discusses the basic properties and mechanisms of Li-S battery separators, focuses on preparing different functionalized separators to mitigate the shuttle effect of polysulfides. This review also introduces future research trends, emphasizing the potential of separator functionalization in advancing the Li-S battery technology.

Caffeic Acid-Zinc Basic Salt/Chitosan Nanohybrid Possesses Controlled Release Properties and Exhibits In Vivo Anti-Inflammatory Activities

Caffeic acid (CA) exhibits a myriad of biological activities including cardioprotective action, antioxidant, antitumor, anti-inflammatory, and antimicrobial properties. On the other hand, CA presents low water solubility and poor bioavailability, which have limited its use for therapeutic applications. The objective of this study was to develop a nanohybrid of zinc basic salts (ZBS) and chitosan (Ch) containing CA (ZBS-CA/Ch) and evaluate its anti-edematogenic and antioxidant activity in dextran and carrageenan-induced paw edema model. The samples were obtained by coprecipitation method and characterized by X-ray diffraction, Fourier transform infrared (FT-IR), scanning electron microscope (SEM) and UV-visible spectroscopy. The release of caffeate anions from ZBS-CA and ZBS-CA/Ch is pH-dependent and is explained by a pseudo-second order kinetics model, with a linear correlation coefficient of R² ≥ 0.99 at pH 4.8 and 7.4. The in vivo pharmacological assays showed excellent anti-edematogenic and antioxidant action of the ZBS-CA/Ch nanoparticle with slowly releases of caffeate anions in the tissue, leading to a prolongation of CA-induced anti-edematogenic and anti-inflammatory activities, as well as improving its inhibition or sequestration antioxidant action toward reactive species. Overall, this study highlighted the importance of ZBS-CA/Ch as an optimal drug carrier.

Efficient Regulation of Polysulfides by Anatase/Bronze TiO2 Heterostructure/Polypyrrole Composites for High-Performance Lithium-Sulfur Batteries

Despite having ultra-high theoretical specific capacity and theoretical energy density, lithium-sulfur (Li-S) batteries suffer from their low Coulombic efficiency and poor lifespan, and the commercial application of Li-S batteries is seriously hampered by the severe "shuttle effect" of lithium polysulfides (LiPSs) and the large volume expansion ratio of the sulfur electrode during cycling. Designing functional hosts for sulfur cathodes is one of the most effective ways to immobilize the LiPSs and improve the electrochemical performance of a Li-S battery. In this work, a polypyrrole (PPy)-coated anatase/bronze TiO₂ (TAB) heterostructure was successfully prepared and used as a sulfur host. Results showed that the porous TAB could physically adsorb and chemically interact with LiPSs during charging and discharging processes, inhibiting the LiPSs' shuttle effect, and the TAB's heterostructure and PPy conductive layer are conducive to the rapid transport of Li⁺ and improve the conductivity of the electrode. By benefitting from these merits, Li-S batteries with TAB@S/PPy electrodes could deliver a high initial capacity of 1250.4 mAh g^-1 at 0.1 C and show an excellent cycling stability (the average capacity decay rate was 0.042% per cycle after 1000 cycles at 1 C). This work brings a new idea for the design of functional sulfur cathodes for high-performance Li-S battery.

A ductile and strong-affinity network binder coupling inorganic oligomers and biopolymers for high-loading lithium-sulfur batteries

Lithium sulfur (Li-S) batteries have become the predominant energy storage devices of the future. However, the reasons why Li-S batteries have not been widely commercialized include the shuttle effect of polysulfides and the volume expansion of sulfur active substances. In this study, a binder with a stretchable 3D reticular structure was induced using inorganic oligomers. Potassium tripolyphosphate (PTP) has been used to powerfully connect the tamarind seed gum (TSG) chain through robust intermolecular forces due to the strong electronegativity of P-O^- groups. With this binder, the volume expansion of sulfur active substances can be well restrained. In addition, a large amount of -OH groups in TSG and P-O^- bonds in PTP can also effectively adsorb polysulfides and inhibit the shuttle effect. Therefore, the S@TSG-PTP electrode shows an improved cycle performance. When the sulfur loading is as high as 4.29 mg cm^-2, the areal specific capacity can reach 3.37 mA h cm^-2 after 70 cycles. This study highlights a new way for the binder design of high-loading sulfur electrodes.

Interfacial Engineering of Binder-Free Janus Separator with Ultra-Thin Multifunctional Layer for Simultaneous Enhancement of Both Metallic Li Anode and Sulfur Cathode

Exploring a scalable strategy to fabricate a multifunctional separator is of great significance to overcome the challenges of lithium polysulfides (LiPSs) and dendritic growth in lithium-sulfur batteries (LSBs). Herein, a binder-free Janus separator is constructed by interfacial engineering. At the cathode interface, an ultra-thin covalent triazine piperazine film containing tailorable micropores and adsorption sites is decorated on polyacrylonitrile (PAN) membrane by in situ interfacial polymerization, building a triple barrier for LiPSs. The combination of steric hindrance and chemical adsorption reduces LiPS's migration by 81.85%. Meanwhile, at the anode interface, a fast-ionic conductor Li_6.4 La₃ Zr_1.4 Ta_0.6 O₁₂  (LLZTO) is created on the surface of PAN nanofiber by magnetron sputtering to suppress dendrite growth. Even though there is no binder between the ceramic layer and the fibrous separator, sputtering creates an inter-embedded structure that ensures no depowering after cycling. Furthermore, the PAN-based separator displays a high temperature tolerance of 180 °C. Consequently, the cell delivers a high capacity of 1287.9 mAh g^-1 at 0.5 C and stable cycling performance with an ultra-low capacity decay rate of 0.059% per cycle over 500 cycles. This work provides a scalable strategy for functionalizing separators to tackle the challenges in LSBs, which is binder-free, stripping-free, and essentially thickening-free.