A Three-Dimensional Fiber-Network-Reinforced Composite Solid-State Electrolyte from Waste Acrylic Fibers for Flexible All-Solid-State Lithium Metal Batteries

Toward Sustainable Polymer Materials for Rechargeable Batteries: Utilizing Natural Feedstocks and Recycling/Upcycling of Polymer Waste

The ever-increasing demand for rechargeable battery systems in the era of electric vehicles has spurred extensive research into developing polymeric components for batteries, such as separators, polymer electrolytes, and binders. However, current battery systems rely on expensive and nonrenewable resources, which potentially have a negative environmental impact. Therefore, polymer materials derived from natural resources have gained significant attention, primarily due to their cost-effective and environmentally sustainable features. Moreover, natural feedstocks often possess highly polar functional groups and high molecular weights, offering desirable electro-chemo-mechanical features when applied as battery materials. More recently, various recycling and upcycling strategies for polymeric battery components have also been proposed given the substantial waste generation from end-of-life batteries. Recycling polymeric materials includes an overall process of recovering the components from spent batteries followed by regeneration into new materials. Polymer upcycling into battery materials involves transforming daily-used plastic waste into high-value-added battery components. This review aims to give a state-of-the-art overview of contemporary methods to develop sustainable polymeric materials and recycling/upcycling strategies for various battery applications.

Recent Progress on Advanced Flexible Lithium Battery Materials and Fabrication Process

Flexible energy storage devices have attracted wide attention as a key technology restricting the vigorous development of wearable electronic products. However, the practical application of flexible batteries faces great challenges, including the lack of good mechanical toughness of battery component materials and excellent adhesion between components, resulting in battery performance degradation or failure when subjected to different types of deformation. It is imperative to develop flexible batteries that can withstand deformation under different conditions and maintain stable battery performance. This paper reviews the latest research progress of flexible lithium batteries, from the research and development of new flexible battery materials, advanced preparation processes, and typical flexible structure design. First, the types of key component materials and corresponding modification technologies for flexible batteries are emphasized, mainly including carbon-based materials with flexibility, lithium anode materials, and solid-state electrolyte materials. In addition, the application of typical flexible structural designs (buckling, spiral, and origami) in flexible batteries is clarified, such as 3D printing and electrospinning, as well as advanced fabrication techniques commonly used in flexible materials and battery components. Finally, the limitations and coping strategies in the practical application of flexible lithium batteries are discussed, which provides new ideas for future research.

Aluminum-Lithium Alloy Fillers Enhancing the Room Temperature Performances of Polymer Electrolytes for All-Solid-State Lithium Batteries

Poly(ethylene oxide) (PEO) electrolytes usually suffer from low room temperature (RT) ionic conductivity and a narrow voltage window, which limits the improvement of energy density and practical applications in all-solid-state batteries. Composite polymer electrolytes (CPEs) are regarded as the common method to reduce the crystallinity of polymers and increase the lithium ion conductivity. Compared with active or inert ceramic material fillers in previous studies, aluminum-lithium alloy fillers are used to prepare composite electrolytes in this study, showing excellent performance at room temperature. The conductivity of the PEO-based electrolytes increases by a factor of 3.62-3.62× 10-4 S cm-1 at RT with 5 wt % Al-Li alloy. The transference number of Li+ is increased to 0.524. The characteristics of the Al-Li alloy and higher conductivity enable the composite electrolyte to stabilize the interface with the electrodes, reducing the polarization of solid-state batteries. The all-solid-state Li/PEO-5%/LiFePO4 cells show the highest initial discharge capacity of 153 mAh g-1 and the highest stable discharge capacity of 147 mAh g-1 with the initial Coulombic efficiency of more than 100%. It also exhibits the best rate capacity and cycle performance (90% capacity retention rate after 100 cycles).

"Peapod-like" Fiber Network: A Universal Strategy for Composite Solid Electrolytes to Inhibit Lithium Dendrite Growth in Solid-State Lithium Metal Batteries

Solid-state lithium metal batteries (SSLMBs) are a promising energy storage technology, but challenges persist including electrolyte thickness and lithium (Li) dendrite puncture. A novel three-dimensional "peapod-like" composite solid electrolyte (CSEs) with low thickness (26.8 μm), high mechanical strength, and dendrite inhibition was designed. Incorporating Li7La3Zr2O12 (LLZO) enhances both mechanical strength and ionic conductivity, stabilizing the CSE/Li interface and enabling Li symmetric batteries to stabilize for 3000 h. With structural advantages, the assembled LFP||Li and NCM811||Li cells exhibit excellent cycling performance. In addition, the constructed NCM811 pouch cell achieves a high gravimetric/volumetric energy density of 307.0 Wh kg-1/677.7 Wh L-1, which can light up LEDs under extreme conditions, demonstrating practicality and high safety. This work offers a generalized strategy for CSE design and insights into high-performance SSLMBs.

Breathable and wearable graphene/waterborne polyurethane coated regenerated polyethylene terephthalate fabrics for motion sensing and thermal therapy

The functional utilization of recycled polymers has emerged as a current prominent and timely subject. Flexible wearable devices with high sensitivity to conductivity have garnered significant attention in the fields of human healthcare monitoring and personal heat management. One significant obstacle that needs to be addressed is the simultaneous maintenance of both sensing functionality and durability in composite fabrics. In this paper, a collection of durable, breathable, and flexible smart fabric was produced using the scratch coating method. The fabrics were created by utilizing a regenerated polyethylene terephthalate fabric as a base material, incorporating graphene microsheets (G) as a conductive agent, and applying a waterborne polyurethane layer as a surface protective coating. Furthermore, an investigation was conducted to assess their sensing performance and electrothermal performance. The composite fabric exhibits significant advantages in terms of high conductivity (592 S/m), wide strain range, high sensitivity (Gauge factor = 6.04) and fantabulous dynamic stability (2000 cycles) at a mass ratio of Graphene/WPU loading of 8:2. These sensors were successfully utilized to monitor various degrees of real-time human body movements, ranging from significant deformation bending of elbows to slight deformation swallowing. Furthermore, the sensors also exhibit a significant electric heating effect. Specifically, when a voltage of 10 V is applied, the sensors can reach a steady state temperature of 53.3 °C within a mere 30 s. This discovery holds potential for the development of wearable heaters that can be used for on-demand thermal therapy, functional protective clothing, and medical electric heating wearables.