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Secondary batteries have been widespread in the daily life causing an ever-growing demand for long-cycle lifespan and high-energy alkali-ion batteries. As an essential constituent part, electrode materials with superior electrochemical properties play a vital role in the battery systems. Here, an outstanding electrode of yolk-shell ZnS@C nanorods is developed, introducing considerable void space via a self-sacrificial template method. Such carbon encapsulated nanorods moderate integral electronic conductivity, thus ensuring rapid alkali-ions/electrons transporting. Furthermore, the porous structure of these nanorods endows enough void space to mitigate volume stress caused by the insertion/extraction of alkali-ions. Due to the unique structure, these yolk-shell ZnS@C nanorods achieve superior rate performance and cycling performance (740 mAh g-1 at 1.0 A g-1 after 540 cycles) for lithium-ion batteries. As a potassium-ion batteries anode, they achieve an ultra-long lifespan delivering 211.1 mAh g-1 at 1.0 A g-1 after 5700 cycles. The kinetic analysis reveals that these ZnS@C nanorods with considerable pseudocapacitive contribution benefit the fast lithiation/delithiation. Detailed transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses indicate that such yolk-shell ZnS@C anode is a typical reversible conversion reaction mechanism accomplished by alloying processes. This rational design strategy opens a window for the development of superior energy storage materials. [ABSTRACT FROM AUTHOR]

For the past few years, a new generation of energy storage systems with large theoretical specific capacity has been urgently needed because of the rapid development of society. Lithium–sulfur (Li−S) batteries are regarded as one of the most promising candidates for novel battery systems, since their resurgence at the end of the 20th century Li−S batteries have attracted ever more attention, attributed to their notably high theoretical energy density of 2600 W h kg−1, which is almost five times larger than that of commercial lithium‐ion batteries (LIBs). One of the determining factors in Li−S batteries is how to design/prepare the sulfur cathode. For the sulfur host, the major technical challenge is avoiding the shuttling effect that is caused by soluble polysulfides during the reaction. In past decades, though the sulfur cathode has developed greatly, there are still some enormous challenges to be conquered, such as low utilization of S, rapid decay of capacity, and poor cycle life. This article spotlights the recent progress and foremost findings in improving the performance of Li−S batteries by employing multifunctional metal phosphides as host materials. The current state of development of the sulfur electrode of Li−S batteries is summarized by emphasizing the relationship between the essential properties of metal phosphide‐based hybrid nanomaterials, the chemical reaction with lithium polysulfides and the latter′s influence on electrochemical performance. Finally, trends in the development and practical application of Li−S batteries are also pointed out. [ABSTRACT FROM AUTHOR]

Recently, Li‐ion batteries (LIBs) have attracted extensive attention owing to their wide applications in portable and flexible electronic devices. Such a huge market for LIBs has caused an ever‐increasing demand for excellent mechanical flexibility, outstanding cycling life, and electrodes with superior rate capability. Herein, an anode of self‐supported Fe3O4@C nanotubes grown on carbon fabric cloth (CFC) is designed rationally and fabricated through an in situ etching and deposition route combined with an annealing process. These carbon‐coated nanotube structured Fe3O4 arrays with large surface area and enough void space can not only moderate the volume variation during repeated Li+ insertion/extraction, but also facilitate Li+/electrons transportation and electrolyte penetration. This novel structure endows the Fe3O4@C nanotube arrays stable cycle performance (a large reversible capacity of 900 mA h g−1 up to 100 cycles at 0.5 A g−1) and outstanding rate capability (reversible capacities of 1030, 985, 908, and 755 mA h g−1 at 0.15, 0.3, 0.75, and 1.5 A g−1, respectively). Fe3O4@C nanotube arrays still achieve a capacity of 665 mA h g−1 after 50 cycles at 0.1 A g−1 in Fe3O4@C//LiCoO2 full cells. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) are the most promising candidates as alternatives to lithium‐ion batteries (LIBs), owing to the natural abundance of sodium salt and the low cost. However, the commercial application of SIBs is principally hampered by the absence of suitable cathode materials. Herein, a novel Na2FeP2O7@carbon/expanded graphite (NFPO@C/EG) composite with a unique microstructure was developed through a scalable sol‐gel process followed by a ball‐milling procedure with expanded graphite. Benefiting from the multiscale carbon‐modified structure, the NFPO@C/EG effectively improves the electronic conductivity and, at the same time, shortens the path of sodium ion transmission. As a consequence, the NFPO@C/EG cathode presents a much higher specific capacity and more stable cycling stability than NFPO@C and NFPO. The unique design of NFPO@C/EG endows a high ratio of pseudocapacitance contribution and a large Na+ diffusion coefficient. As a consequence, the NFPO@C/EG cathode displays stable cycle performance (82 mAh g−1 over 400 cycles at 232 mA g−1) and superior rate capability (60 mAh g−1 at a high charge/discharge density of 2320 mA g−1). This multiscale carbon‐modified design concept builds an avenue for the practical application of polyanionic cathode materials and promotes the development of low‐cost SIBs. [ABSTRACT FROM AUTHOR]

Keywords: Li-ion batteries; high-energy density; sulfur; metal phosphides EN Li-ion batteries high-energy density sulfur metal phosphides 1 1 1 09/28/21 20210924 NES 210924 In addition to avoiding the shuttling caused by soluble polysulfides, the design and preparation of sulfur cathodes for Li-S batteries must overcome challenges such as the low use of S, rapid decay of capacity and poor cycle life. This review spotlights recent progress in improving the performance of Li-S batteries by employing multifunctional metal phosphides as host materials. Frontispiece: Multifunctional Metal Phosphides as Superior Host Materials for Advanced Lithium-Sulfur Batteries. [Extracted from the article]

The cathode, a crucial constituent part of Li-ion batteries, determines the output voltage and integral energy density of batteries to a great extent. Among them, Ni-rich LiNixCoyMnzO2 (x + y + z = 1, x ≥ 0.6) layered transition metal oxides possess a higher capacity and lower cost as compared to LiCoO2, which have stimulated widespread interests. However, the wide application of Ni-rich cathodes is seriously hampered by their poor diffusion dynamics and severe voltage drops. To moderate these problems, a nanobrick Ni-rich layered LiNi0.6Co0.2Mn0.2O2 cathode with a preferred orientation (110) facet was designed and successfully synthesized via a modified co-precipitation route. The galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) analysis of LiNi0.6Co0.2Mn0.2O2 reveal its superior kinetic performance endowing outstanding rate performance and long-term cycle stability, especially the voltage drop being as small as 67.7 mV at a current density of 0.5 C for 200 cycles. Due to its unique architecture, dramatically shortened ion/electron diffusion distance, and more unimpeded Li-ion transmission pathways, the current nanostructured LiNi0.6Co0.2Mn0.2O2 cathode enhances the Li-ion diffusion dynamics and suppresses the voltage drop, thus resulting in superior electrochemical performance. [ABSTRACT FROM AUTHOR]

Alloying with Se has been recently found to be an effective way to improve the cycling performance because the reduced-Se formations can act as a buffer matrix against the volume change of electrode for IVA materials or anchors S in Li-S batteries during cycling. In this paper, SnSe nanoparticles were dispersed within a carbon fiber matrix with ball milling and electrospinning methods. The uniform nano-architecture with SnSe nanoparticles homogeneously confined in the carbon matrix, which is revealed by X-ray powder diffraction and scanning electron microscope, provides a stable buffer and good electrical conductor for the lithiation/delithiation process. Moreover, Se-based phase acts as an additional stabilizer to alleviate Sn agglomeration during cycling. Such dual-buffered SnSe/C composites thus deliver large reversible capacity of 840 mAh/g with ultrastable cycling performance over 100 cycles and demonstrate good rate capacity. [ABSTRACT FROM AUTHOR]