Xuehan Wang

Thanks to the unique rigid conformation and designable side‐chain structure, helical polymers are starting to be more widely considered as ideal electrode materials in secondary batteries. In this study, a series of helical poly(isocyanide anthraquinones) (PIC‐AQs), including PIC‐1AQ_n and PIC‐2AQ_n, were designed and synthesized via living polymerization using a palladium catalyst (Pd‐II). The polymers feature a helical polyisocyanide main chain and anthraquinone (AQ) pendants, offer high yields (approximately 90%), controlled number‐average molecular weight (M_n), and a low polymer dispersity index (PDI). Attributed to a narrow energy band gap, low unoccupied molecular orbitals, and high spatial freedom of PIC‐2AQ, it exhibits excellent long‐term stability in lithium metal batteries (LMBs), maintaining 141 mAh g⁻¹ after 2000 cycles at 1 A g⁻¹. Additionally, an in situ polymerized poly(ionic liquid) electrolyte was prepared for assembling a PIC‐2AQ all‐solid‐state soft‐pouch battery. And it remained stable under extreme operations like bending or cutting. Such a battery significantly broadens the application scope of organic LMBs and offers great potential for their use in flexible electronic devices.

Electrochromic (EC) technology has become one of the smart technologies with the most potential for development and application at this stage. Based on electrochromic devices (ECDs), this technology has shown extraordinary potential in the fields of smart windows, display devices, and sensing systems. With the optimization and iteration of various core components in ECDs, the electrolyte layer, a key component, evolved from its initial liquid state to a quasi-solid state and solid state. As driven by increasing application demands, the development trend indicates that all-solid-state, transparent electrolytes will likely become the future form of the electrolyte layer. Recently, the application of ionic liquid (IL)-based electrolytes in the field of electrochromism attracted a lot of attention due to their ability to bring outstanding EC cycling stability, thermal stability, and a wider operating voltage range to ECDs, and they are regarded as the new generation of electrolyte materials with the most potential for application. Although compared with conventional electrolytes, IL-based electrolytes have the characteristics of high price, high viscosity, and low conductivity, they are still considered the most promising electrolyte materials for applications. However, so far, there has been a lack of comprehensive analysis reports on “Research progress in ionic liquid-based electrolytes for electrochromic devices” within the EC field. In this article, the research progress of IL-based electrolytes in ECDs will be summarized from three perspectives: liquid, quasi-solid, and solid state. The future development directions of IL-based electrolytes for ECDs are discussed.

Solid-state electrolytes (SSEs), particularly garnet-type Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO), offer high stability and a wide electrochemical window. However, their grain boundaries limit ionic conductivity, necessitating high-temperature sintering for improved performance. Yet, this process results in brittle electrolytes prone to fracture during manufacturing. To address these difficulties, solvent-free solid-state electrolytes with a polyacrylonitrile (PAN) coating on LLZTO particles are reported in this work. Most notably, the PAN-coated LLZTO (PAN@LLZTO) electrolyte demonstrates self-supporting characteristics, eliminating the need for high-temperature sintering. Importantly, the homogeneous polymeric PAN coating, synthesized via the described method, facilitates efficient Li⁺ transport between LLZTO particles. This electrolyte not only achieves an ionic conductivity of up to 2.11 × 10⁻³ S cm⁻¹ but also exhibits excellent interfacial compatibility with lithium. Furthermore, a lithium metal battery incorporating 3% PAN@LLZTO-3%PTFE as the solid-state electrolyte and LiFePO₄ as the cathode demonstrates a remarkable specific discharge capacity of 169 mAh g⁻¹ at 0.1 °C. The strategy of organic polymer-coated LLZTO provides the possibility of a green manufacturing process for preparing room-temperature sinter-free solid-state electrolytes, which shows significant cost-effectiveness.

As a popular energy storage equipment, lithium-ion batteries (LIBs) have many advantages, such as high energy density and long cycle life. At this stage, with the increasing demand for energy storage materials, the industrialization of batteries is facing new challenges such as enhancing efficiency, reducing energy consumption, and improving battery performance. In particular, the challenges mentioned above are particularly critical in advanced next-generation battery manufacturing. For batteries, the electrode processing process plays a crucial role in advancing lithium-ion battery technology and has a significant impact on battery energy density, manufacturing cost, and yield. Dry electrode technology is an emerging technology that has attracted extensive attention from both academia and the manufacturing industry due to its unique advantages and compatibility. This paper provides a detailed introduction to the development status and application examples of various dry electrode technologies. It discusses the latest advancements in commonly used binders for different dry processes and offers insights into future electrode manufacturing.

Phenazine-based redox-active centers are capable of averting chemical bond rearrangements by coupling during the reaction process, leading to enhanced stabilization of the material. When introduced into a high-performance polymer with excellent physicochemical properties, they can be endowed with electrochemical properties and related prospective applications while maintaining the capabilities of the materials. In this study, a facile C-N coupling method was chosen for the synthesis of serial poly(aryl ether sulfone) materials containing phenazine-based redox-active centers and to explore their electrochemical properties. As expected, the cyclic voltammetry curves of PAS-DPPZ-60, which basically overlap after thousands of cycles, indicate the stability of the electrochemical properties. As an electrochromic material, the transmittance change in PAS-DPPZ-60 exhibits only a slight attenuation after as long as 600 cycles. Meanwhile, as an organic battery cathode material, PAS-DPPZ has a theoretical specific capacity of 126 mAh g⁻¹, and the capacity retention rate is 82.6% after 100 cycles at a 0.1 C current density. The perfect combination of advantageous features between phenazine and poly(aryl ether sulfone) is considered to be the reason for the favorable electrochemical performance of the material series.

Lithium-ion batteries (LIBs) have recently become popular for energy storage due to their high energy density, storage capacity, and long-term cycle life. Although binders make up only a small proportion of LIBs, they have become the key to promoting the transformation of the battery preparation process. Along with the development of binders, the battery manufacturing process has evolved from the conventional slurry-casting (SC) process to a more attractive solvent-free (SF) method. Compared with traditional LIBs manufacturing method, the SF method could dramatically reduce and increase the energy density due to the reduced preparation steps and enhanced electrode loading. Polytetrafluoroethylene (PTFE), as a typical binder, has played an important role in fabricating high-performance LIBs, particularly in regards to the SF technique. In this paper, the development history and application status of PTFE binder was introduced, and then its contributions and the inherent problems involved in the SF process were described and analyzed. Finally, the viewpoints concerning the future trends for PTFE-based SF manufacturing methods were also discussed. We hope this work can inspire future research concerning high-quality SF binders and assist in promoting the evolution of the SF manufacturing technology in regards to LIBs.

Organic electrode materials (OEMs) have attracted intensive attention owing to their high energy density, diverse structures and environmental friendliness. Unfortunately, the easy dissolution of OEMs in the organic liquid electrolytes (OLEs) severely damages the cycle stability of batteries. There is a hidden danger of catching fire due to a lot of heat generated from overcharge of the batteries. Moreover, OLEs are liable to leak and unstable at high voltage. Using solid‐state electrolytes (SSEs) could effectively alleviate the above‐mentioned problems at some extent. However, SSEs still show some weaknesses, including the large impedance of electrolyte‐electrode interface (EEI) and low ion conductivity. In this review, the latest progress in the research of SSEs used in organic secondary batteries (OSBs) are summarized, with particularly focus on the ionic conductivity of SSEs, the combination of organic electrodes/solid‐state electrolytes, the optimization of EEI and the batteries cycle stability. Future directions for the development of OSBs are given from viewpoints of solid batteries.

This review divides the active sites of COFs into four categories: carbonyl, phenyl, imine bonds and other groups, and introduces their applications in LIBs.