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Black phosphorus–carbon (BP–C) composite is a potential high‐energy anode material for lithium‐ion batteries (LIBs); however, the local stress concentration that occurs during lithiation/delithiation cycling leads to poor cycling performance. Herein, an electrochemically inactive TiP nanocrystal is used to reconstruct the BP–C composite via ball milling to form a BP–TiP–C multiphase structure with excellent lithium storage performance. The TiP intermediate optimizes the TiP–BP interface and relieves the local stress of the BP–TiP–C composite, thereby enhancing the electron transfer, structural stability, and utilization of the active material. This BP–TiP–C composite exhibits a high coulombic efficiency of 99.85%, an enhanced cyclic stability of 557.6 mAh g−1 after 1000 cycles with a 72.5% capacity retention at 2.0 A g−1, and an excellent rate performance of 548.2 mAh g−1 at 10.0 A g−1. Thus, this study not only provides a high‐energy BP–TiP–C material, but also offers new ideas for material synthesis to advance the research on BP‐based LIBs. [ABSTRACT FROM AUTHOR]

The separator, as an important inner part of the sodium‐ion battery (SIB), has a significant impact on the electrochemical performance and security of the battery. However, conventional polyolefin separators are inapplicable for SIBs due to their poor wettability to liquid electrolytes and unsatisfactory heat resistance. To address these problems, a novel polyethylene (PE)‐ hydroxyethyl cellulose (HEC)‐TiO2 composite separator modified on the PE matrix is proposed and successfully prepared by a multistep synthesis procedure of HEC coating and TiO2 in situ self‐growth, while almost maintaining the initial separator thickness. Compared with conventional PE separators, this composite separator possesses remarkable wettability which benefits from the introduction of a polar HEC‐TiO2‐incorporated coating. Besides, thanks to a significant improvement in wettability, the separator presents high electrolyte uptake of up to 186.5% and an extraordinary ionic conductivity of 0.342 mS cm−1. As expected, a Na|Na3V2(PO4)3 battery with the PE‐HEC‐TiO2 separator exhibits a reversible capacity of 99.0 mAh g−1 and a capacity retention of 94.8% after 1000 cycles at 5 C with a steady Coulombic efficiency of nearly 100%. These brilliant performances convincingly make it a promising separator for advanced SIBs with high reversibility, high capacity, and long life. [ABSTRACT FROM AUTHOR]

Based on a strategy of stabilizing the LiMn2O4 (LMO) cathode interface, the high‐temperature cycling and storage performance of 18 650‐type LMO/graphite lithium‐ion batteries (LIBs) is effectively improved. The LMO cathode is prepared using lithium carboxymethyl cellulose (CMCLi)–polyacrylic acid/acrylate copolymer composite binder and nanoscale CaCO3 functional component (marked as binder C). Compared with the traditional oily binder, the dissolution of Mn2+ from LMO cathode into the electrolyte can effectively decrease, and the structure stability of LMO cathode can increase. The batteries exhibit retention capacity of 80.3% at 1 C after 600 cycles at room temperature and 76.7% at 1 C after 200 cycles at temperature of 45 °C. The high‐temperature storage performance is also improved and there are 81.1% and 73.5% residual capacities when the fully charged batteries are stored in 60 °C for 14 and 28 days. The enhanced performance is mainly attributed to the interfacial stability of LMO cathode due to the bonding ability of composite binders and the elimination of HF by CaCO3. These results reveal the application prospect of as‐developed aqueous binders and provide a way to improve the performance of LMO‐based LIBs through stable interface strategy. [ABSTRACT FROM AUTHOR]

Iron oxides are considered as potential anode materials for lithium‐ion batteries thanks to their high theoretical capacity, rich resources, and environmental friendliness. However, the rapid capacity decay and sluggish kinetics greatly limit their practical application. Herein, a simple surface fluorination strategy is developed to greatly improve the electrochemical properties of Fe3O4. The fluorinated layer can act as a protective film to stabilize the electrode/electrolyte interface, enhance the wettability of the electrode to shorten the Li+ diffusion pathway, and provide more active centers to facilitate charge storage. Consequently, the fabricated fluorinated Fe3O4 electrode demonstrates high specific capacity (1379 mAh g−1 at 0.5 A g−1 after 300 cycles) and impressive high‐rate performance (876, 802, and 456 mAh g−1 at 5, 10, and 20 A g−1, respectively, after 1000 cycles), which outperforms most of the Fe3O4‐based electrodes recorded so far. This material design strategy may open up a new way for the development of high‐performance anode materials for energy storage based on earth‐rich materials, and advance the understanding of the core role of electrode surfaces/interfaces in battery systems. [ABSTRACT FROM AUTHOR]

A positive‐temperature‐coefficient graphite anode as a thermal runaway firewall of LiCoO2/graphite lithium‐ion batteries (LIBs) is prepared by introducing thermally sensitive polymer microspheres (TSPMs) into the anode to improve battery safety under abusive conditions. The TSPMs are composed of an acrylonitrile and acrylate copolymer shell and a cyclopentane hydrocarbon core. Due to the thermally sensitive properties of TSPMs, the graphite anode swells under abusive conditions, and the electric connection of active materials and current collector can be cut off. Thus, the resistance of LIBs is increased to solve the thermal runaway and safety problems before the temperature of LIBs approaches explosion limit. The TSPMs with a size distribution of 4–20 μm and an initial foaming temperature of 95–110 °C exhibit excellent stability and foaming properties. Compared with the batteries without TSPMs, under abusive conditions including overcharge at 1 C/10 V, thermal shock from 20 to 130 °C, and external short circuit with a resistance of ≈80 mΩ, the batteries with TSPMs effectively mitigate thermal runaway. In addition, TSPMs do not show obvious influences on the conventional performances of LIBs, indicating that adding TSPMs into graphite anodes is a promising method to improve the safety of LIBs under abusive conditions. [ABSTRACT FROM AUTHOR]

Three‐dimensional (3D) SiOx‐based membrane anodes with stabilized electrochemical performances for lithium‐ion batteries are fabricated ingeniously using high‐capacity SiOx active material. The flexible self‐supporting substances of poly(vinylidene fluoride) and carbon nanotubes are chosen as the supporting substances, which not only provide the 3D framework for the flexible self‐supporting membrane but also act as a protective layer with enhanced conductive pathway. In particular, this unique 3D structure can prevent the SiOx surface from contacting the electrolyte directly and can buffer the volumetric expansion of SiOx particles. This optimized membrane anode exhibits a high reversible specific capacity of 1436 mAh g−1 and a capacity retention rate of 88% after 100 cycles. In addition, it also demonstrates an outstanding rate performance, a specific capacity of 1245 mAh  g−1 is obtained at 1200 mA g−1, which is about 91% at 100 mA g−1. The stabilized performances of the as‐prepared membrane anodes indicate their promising prospects in the practical applications, and the fabricating method also provides a reference for the preparation of other flexible self‐supporting membrane electrodes. Poly(vinylidene fluoride) (PVDF) and carbon nanotubes (CNTs) provide a framework for the membrane, in which SiOx is stably embedded to prevent corrosion from direct contact with the electrolyte. Due to the excellent structural characteristics, 3D SiOx‐based membrane anodes with stable electrochemical performances are obtained. The preparation method of such a flexible self‐supporting film provides a reference for other flexible materials. [ABSTRACT FROM AUTHOR]