Owing to high specific energy, low cost, and environmental friendliness, lithium–sulfur (Li–S) batteries hold great promise to meet the increasing demand for advanced energy storage beyond portable electronics, and to mitigate environmental problems. However, the application of Li–S batteries is challenged by several obstacles, including their short life and low sulfur utilization, which become more serious when sulfur loading is increased to the practically accepted level above 3–5 mg cm−2. More and more efforts have been made recently to overcome the barriers toward commercially viable Li–S batteries with a high sulfur loading. This review highlights the recent progress in high-sulfur-loading Li–S batteries enabled by hierarchical design principles at multiscale. Particularly, basic insights into the interfacial reactions, strategies for mesoscale assembly, unique architectures, and configurational innovation in the cathode, anode, and separator are under specific concerns. Hierarchy in the multiscale design is proposed to guide the future development of high-sulfur-loading Li–S batteries.

Review on High-Loading and High-Energy Lithium–Sulfur Batteries

The ever-growing demand for advanced rechargeable lithium-ion batteries in portable electronics and electric vehicles has spurred intensive research efforts over the past decade. The key to sustaining the progress in Li-ion batteries lies in the quest for safe, low-cost positive electrode (cathode) materials with desirable energy and power capabilities. One approach to boost the energy and power densities of batteries is to increase the output voltage while maintaining a high capacity, fast charge–discharge rate, and long service life. This review gives an account of the various emerging high-voltage positive electrode materials that have the potential to satisfy these requirements either in the short or long term, including nickel-rich layered oxides, lithium-rich layered oxides, high-voltage spinel oxides, and high-voltage polyanionic compounds. The key barriers and the corresponding strategies for the practical viability of these cathode materials are discussed along with the optimization of electrolytes and other cell components, with a particular emphasis on recent advances in the literature. A concise perspective with respect to plausible strategies for future developments in the field is also provided.

High-voltage positive electrode materials for lithium-ion batteries

The storage of electric energy is of ever growing importance for our modern, technology-based society, and novel battery systems are in the focus of research. The substitution of conventional metals as redox-active material by organic materials offers a promising alternative for the next generation of rechargeable batteries since these organic batteries are excelling in charging speed and cycling stability. This review provides a comprehensive overview of these systems and discusses the numerous classes of organic, polymer-based active materials as well as auxiliary components of the battery, like additives or electrolytes. Moreover, a definition of important cell characteristics and an introduction to selected characterization techniques is provided, completed by the discussion of potential socio-economic impacts.

Polymer-Based Organic Batteries

Tremendous efforts have been devoted to the development of electrode materials, electrolytes, and separators of energy-storage devices to address the fundamental needs of emerging technologies such as electric vehicles, artificial intelligence, and virtual reality. However, binders, as an important component of energy-storage devices, are yet to receive similar attention. Polyvinylidene fluoride (PVDF) has been the dominant binder in the battery industry for decades despite several well-recognized drawbacks, i.e., limited binding strength due to the lack of chemical bonds with electroactive materials, insufficient mechanical properties, and low electronic and lithium-ion conductivities. The limited binding function cannot meet inherent demands of emerging electrode materials with high capacities such as silicon anodes and sulfur cathodes. To address these concerns, in this review we divide the binding between active materials and binders into two major mechanisms: mechanical interlocking and interfacial b...

Exploring Chemical, Mechanical, and Electrical Functionalities of Binders for Advanced Energy-Storage Devices

Review on Challenges and Recent Advances in the Electrochemical Performance of High Capacity Li‐ and Mn‐Rich Cathode Materials for Li‐Ion Batteries

Binders have been reported to play a key role in improving the cycle performance of Si anode materials of lithium-ion batteries. In this study, the biopolymer guar gum (GG) is applied as the binder for a silicon nano­particle (SiNP) anode of a lithium-ion battery for the first time. Due to the large number of polar hydroxyl groups in the GG molecule, a robust interaction between the GG binder and the SiNPs is achieved, resulting in a stable Si anode during cycling. More specifically, the GG binder can effectively transfer lithium ions to the Si surface, similarly to polyethylene oxide solid electrolytes. When GG is used as a binder, the SiNP anode can deliver an initial discharge capacity as high as 3364 mAh g−1, with a Coulombic efficiency of 88.3% at the current density of 2100 mA g−1, and maintain a capacity of 1561 mAh g−1 after 300 cycles. The study shows that the electrochemical performance of the SiNP anode with GG binder is significantly improved compared to that of a SiNP anode with a sodium alginate binder, and it demonstrates that GG is a promising binder for Si anodes of lithium-ion batteries.

A Robust Ion‐Conductive Biopolymer as a Binder for Si Anodes of Lithium‐Ion Batteries

Li-rich materials, Li1.140Mn0.622Ni0.114Co0.124O2, of a layered/spinel heterostructure were synthesized by a one-step solvothermal route with subsequent moderate heat treatment. The as-prepared materials consist of hierarchical microspheres and an integral layered/spinel heterostructure. The effects of calcination time on both the structure and electrochemical performance of materials have been studied systematically. It has been found that the formation of the spinel structure could be controlled by adjusting the calcination time at 650 °C, and the materials calcined at this temperature for 24 hours present the optimal electrochemical performance. High initial efficiencies of 101% at 0.2C and 92% at 2C, as well as high discharge capacities of 280, 256, 234 and 206 mA h g−1 respectively at 1C, 2C, 5C and 10C have been achieved. The empty 16c octahedral site and 3D Li+ diffusion channel provided by the spinel have been regarded as the key to the improvement of electrochemical performances.

Layered/spinel heterostructured Li-rich materials synthesized by a one-step solvothermal strategy with enhanced electrochemical performance for Li-ion batteries

Tao Zhang

Papers

A Robust Ion‐Conductive Biopolymer as a Binder for Si Anodes of Lithium‐Ion Batteries

Layered/spinel heterostructured Li-rich materials synthesized by a one-step solvothermal strategy with enhanced electrochemical performance for Li-ion batteries

Multiple hydrogel alginate binders for Si anodes of lithium-ion battery

Suppressing the voltage-fading of layered lithium-rich cathode materials via an aqueous binder for Li-ion batteries

P2-type Na0.67Mn0.72Ni0.14Co0.14O2 with K+ doping as new high rate performance cathode material for sodium-ion batteries