Covalent organic frameworks (COF) possess a robust and porous crystalline structure, making them an appealing candidate for energy storage. Herein, we report an exfoliated polyimide COF composite ...(P‐COF@SWCNT) prepared by an in situ condensation of anhydride and amine on the single‐walled carbon nanotubes as advanced anode for potassium‐ion batteries (PIBs). Numerous active sites exposed on the exfoliated frameworks and the various open pathways promote the highly efficient ion diffusion in the P‐COF@SWCNT while preventing irreversible dissolution in the electrolyte. During the charging/discharging process, K+ is engaged in the carbonyls of imide group and naphthalene rings through the enolization and π‐K+ effect, which is demonstrated by the DFT calculation and XPS, ex‐situ FTIR, Raman. As a result, the prepared P‐COF@SWCNT anode enables an incredibly high reversible specific capacity of 438 mA h g−1 at 0.05 A g−1 and extended stability. The structural advantage of P‐COF@SWCNT enables more insights into the design and versatility of COF as an electrode.
We prepare a polyimide covalent organic framework composite anode by effective in‐situ condensation of anhydride and amine on the surface of single‐walled carbon nanotubes. The construction of the conductive network accelerates the transport of electron. Dual electroactive sites in the framework, carbonyls and aromatic naphthalene rings, could store more potassium ions by the enolization and π‐K+ effect.
Sodium‐ion batteries (SIBs) have great potential for large‐scale energy storage. Cellulose is an attractive material for sustainable separators, but some key issues still exist affecting its ...application. Herein, a cellulose‐based composite separator (CP@PPC) was prepared by immersion curing of cellulose‐based separators (CP) with poly(propylene carbonate) (PPC). With the assistance of PPC, the CP@PPC separator is able to operate the cell stably at high voltages (up to 4.95 V). The “pore‐hopping” ion transport mechanism in CP@PPC opens up extra Na+ migration paths, resulting in a high Na+ transference number (0.613). The separator can also tolerate folding, bending and extreme temperature under certain circumstances. Full cells with CP@PPC reveal one‐up capacity retention (96.97 %) at 2C after 500 cycles compared to cells with CP. The mechanism highlights the merits of electrolyte analogs in separator modification, making a rational design for durable devices in advanced energy storage systems.
Immersion curing of a cellulose‐based separator (CP) with poly(propylene carbonate) (PPC) results in a cellulose‐based composite separator (CP@PPC) for sodium‐ion batteries. The “pore‐hopping” ion transport mechanism in CP@PPC allows a high Na+ transference number. PPC enhances the mechanical properties of the separator and the battery thermal safety, further promotes ion transport and improves the overall performance of the battery.
A new metal–organic framework {(Me2NH2)2Co3(μ3-O)(btb)2(py)(H2O)·(DMF)2(H2O)2}n (Cobtbpy) was solvothermal synthesized (H3btb = 1,3,5-tri(4-carboxylphenyl)benzene, py = pyridine, DMF = ...N,N-dimethylformamide). Cobtbpy shows a (3,6)-connected rtl 3D network with a point symbol of (4·62)2(42·610·83) based on the Co3(μ3-O) clusters. The obtained Cobtbpy has stable, accessible, dense active sites and can be applied in the potassium- and sodium-ion batteries. Through mixing with single-walled carbon nanotubes, the prepared composite anode material Cobtbpy-0.9 achieved a high reversible capability, delivering 416 mAh/g in the potassium-ion batteries and 379 mAh/g in the sodium-ion batteries at 0.05 A/g. The outstanding properties of Cobtbpy-0.9 in the batteries demonstrated that this MOFs-based carbon composite is a highly desirable electrode material candidate for high-performance potassium- and sodium-ion batteries.
Covalent organic frameworks (COFs) have received increased interest in recent years as an advanced class of materials. By virtue of the available monomers, multiple conformations and various ...linkages, COFs offer a wide range of opportunities for complex structural design and specific functional development of materials, which has facilitated the widespread application in many fields, including multi‐valent metal ion batteries (MVMIBs), described as the attractive candidate replacing lithium‐ion batteries (LIBs). With their robust skeletons, diverse pores, flexible structures and abundant functional groups, COFs are expected to help realize a high performance MVMIBs. In this review, we present an overview of COFs, describe advances in topology design and synthetic reactions, and study the application of COFs in MVMIBs, as well as discuss challenges and solutions in the preparation of COFs electrodes, in the hope of providing constructive insights into the future direction of COFs.
Covalent organic frameworks (COFs) offer an opportunity for complex structural design and specific functional development, facilitating, for example, the applications of multi‐valent metal ion batteries (Zn2+, Mg2+, Al3+). This comprehensive review describes COF synthesis and applications, provides advances in topology design and synthetic reactions, surveys the application of COFs in multi‐valent ion batteries, discusses the key issues of COF electrodes, and predicts future applications.
Solid‐state lithium‐sulfur batteries have shown prospects as safe, high‐energy electrochemical storage technology for powering regional electrified transportation. Owing to limited ion mobility in ...crystalline polymer electrolytes, the battery is incapable of operating at subzero temperature. Addition of liquid plasticizer into the polymer electrolyte improves the Li‐ion conductivity yet sacrifices the mechanical strength and interfacial stability with both electrodes. In this work, we showed that by introducing a spherical hyperbranched solid polymer plasticizer into a Li+‐conductive linear polymer matrix, an integrated dynamic cross‐linked polymer network was built to maintain fully amorphous in a wide temperature range down to subzero. A quasi‐solid polymer electrolyte with a solid mass content >90 % was prepared from the cross‐linked polymer network, and demonstrated fast Li+ conduction at a low temperature, high mechanical strength, and stable interfacial chemistry. As a result, solid‐state lithium‐sulfur batteries employing the new electrolyte delivered high reversible capacity and long cycle life at 25 °C, 0 °C and −10 °C to serve energy storage at complex environmental conditions.
We demonstrate a fully amorphous quasi‐solid polymer electrolyte with a dynamic cross‐linked network composed of a star‐shaped plasticising polymer and a linear poly‐1,3‐dioxolane. The electrolyte achieves high Li+ conductivity (2.96×10−4 S cm−1) and high tLi+ (0.81), and the as‐prepared solid‐state lithium‐sulfur batteries exhibit high reversible capacity and long cycle life when operating at subzero temperature conditions.
Along with the explosive growth in the market of new energy electric vehicles, the demand for Li-ion batteries (LIBs) has correspondingly expanded. Given the limited life of LIBs, numbers of spent ...LIBs are bound to be produced. Because of the severe threats and challenges of spent LIBs to the environment, resources, and global sustainable development, the recycling and reuse of spent LIBs have become urgent. Herein, we propose a novel green and efficient direct recycling method, which realizes the concurrent reuse of LiFePO
4
(LFP) cathode and graphite anode from spent LFP batteries. By optimizing the proportion of LFP and graphite, a hybrid LFP/graphite (LFPG) cathode was designed for a new type of dualion battery (DIB) that can achieve co-participation in the storage of both anions and cations. The hybrid LFPG cathode combines the excellent stability of LFP and the high conductivity of graphite to exhibit an extraordinary electrochemical performance. The best compound, i.e., LFP:graphite = 3:1, with the highest reversible capacity (∼130 mA h g
−1
at 25 mA g
−1
), high voltage platform of 4.95 V, and outstanding cycle performance, was achieved. The specific diffusion behavior of Li
+
and PF
6
−
in the hybrid cathode was studied using electrode kinetic tests, further clarifying the working mechanism of DIBs. This study provides a new strategy toward the large-scale recycling of positive and negative electrodes of spent LIBs and establishes a precedent for designing new hybrid cathode materials for DIBs with superior performance using spent LIBs.
Dual‐ion batteries (DIBs) have attracted great research interests owing to the co‐utilization of cation and anion as charge carriers. Unlike the low energy density (Eden) of supercapacitors and ...halogen‐ion batteries also with anion working, graphite‐cathode‐based DIBs exhibit obviously higher Eden with high working voltage. However, general electrolytes cannot satisfy the high‐energy demand for Na‐based DIBs with high power density. Herein, we design an effective electrolyte with optimized performance to limit the occurrence of side reactions during cycling, improving the cycling stability and Eden of Na‐based DIBs. Such electrolyte‐modified Na‐DIBs exhibit higher discharge plateau and specific capacity compared to the pristine batteries, contribute preeminent Eden of 370.4 Wh/kg at a high‐power density of 8888.4 W/kg (2.0 A/g), and deliver higher capacity retention of 72 % after 1000 cycles under 40 °C (1.0 A/g). All of these improvements are attributed to the interphase protection of anode/cathode by modified electrolyte, and the increase of diffusion ability under high potential. This strategy not only provides reference significance for enhancing the performance of DIBs, but also promotes the development of DIBs with high‐power/energy and long‐term cycle working condition.
It's all about the electrolyte: In this work, a new modified electrolyte is used for Na‐based dual‐ion battery (Na‐DIB). This modified Na‐DIB shows outstanding electrochemical performance, especially high power/energy density and long‐cycling stability. This modification technique paves the way for the design of Na‐DIB electrolytes and promotes the application of Na‐DIB.
Covalent organic frameworks (COFs) have the virtues of available monomers, multiple conformations and various linkages, and hence offer an opportunity for complex structural design and specific ...functional development, which can facilitate the electrochemical properties of multi‐valent metal ion batteries (MVMIBs). In this review, H.‐Y. Lü, X.‐L. Wu and co‐workers describe advances in design and synthesis of COFs, and survey its application in MVMIBs, in the hope of providing constructive insights into the future direction of COFs (DOI: 10.1002/chem.202202723).
Lithium (Li) metal has been considered to be the most promising anode material for next-generation rechargeable batteries. Unfortunately, the hazards induced by dendrite growth and volume fluctuation ...hinder its commercialized application. Here, a three-dimensional (3D) current collector composed of a vertically aligned Cu2O nanowire that is tightly coated with a polydopamine protective layer is developed to solve the encountered issues of lithium metal batteries (LMBs). The Cu2O nanowire arrays (Cu2O NWAs) provide abundant lithiophilic sites for inducing Li nucleation selectively to form a thin Li layer around the nanowires and direct subsequent Li deposition. The well-defined nanochannel works well in confining the Li growth spatially and buffering the volume change during the repeated cycling. The PDA coatings adhered onto the outline of the Cu2O NWAs serve as the artificial solid electrolyte interface to isolate the electrode and electrolyte and retain the interfacial stability. Moreover, the increased specific area of copper foam (CF) can dissipate the local current density and further suppress the growth of Li dendrites. As a result, CF@Cu2O NWAs@PDA realizes a dendrite-free morphology and the assembled symmetrical batteries can work stably for over 1000 h at 3 mA cm–2. When CF@Cu2O NWAs@PDA is coupled with a LiFePO4 cathode, the full cells exhibit improved cycle stability and rate performance.
In recent years, rechargeable aqueous zinc-ion batteries (ZIBs) have shown extraordinary potential due to their safety, nontoxicity, sustainable zinc resources, and low price. However, the lack of ...suitable cathode materials hinders the development of ZIBs. Recently, layered phosphates have been widely used as cathode materials. As one typical phosphate cathode, vanadium oxyphosphate (VOPO4) has inherently low electronic conductivity and structural dissolution in electrochemical reactions, limiting its development. To solve these problems, VOPO4/C is prepared by combining multifunctional carbon material with a VOPO4 interlayer and an external surface, which not only improves the electronic conductivity of the composite material but also effectively inhibits the dissolution of VOPO4 in the electrolyte. As a result, the prepared VOPO4/C could deliver a reversible capacity of 140 mA h g–1 at a current density of 100 mA g–1. Furthermore, the rate performance of the VOPO4/C composite has also been improved significantly. In the process of charging and discharging, zinc ions in the composite show perfect intercalate and deintercalate performance.
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