Search

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. [ABSTRACT FROM AUTHOR]

Cobalt‐free LiNiO2 is an attractive cathode material with high energy density and low cost but suffers from severe structural degradation and poor performance. Here, a molten salt‐assisted synthesis combined with a Li‐refeeding strategy is proposed to obtain nonstoichiometric Li1+xNi1‐xO2 with submicron particle size and superior rate performance. The slightly Li‐rich and single‐crystalline characters inhibit Li+/Ni2+ anti‐site defects and mitigates the undesirable phase evolution. Remarkably, single‐crystalline Li1.045Ni0.955O2 exhibits a high specific capacity (218.7 mAh g−1 at 0.1 C), considerable rate capability (187.0 mAh g−1 at 5 C), and an initial Coulombic efficiency (89.62% at 0.1 C) in the 1.27 Ah pouch full cell employing the graphite anode, significantly outperforming near stoichiometric LiNiO2. Furthermore, the particulate morphology of Li1.045Ni0.955O2 remains intact at charge voltages up to 4.8 V, whereas near stoichiometric LiNiO2 features intragranular cracks and irreversible lattice distortion. This study underscores the value of molten salt‐assisted synthesis and Li‐refeeding modification to upgrade Ni‐based layered oxide cathode materials for advanced Li‐ion batteries. [ABSTRACT FROM AUTHOR]

The wollastonite was grafted with different silane coupling agents, which could improve interface adhesion. Wollastonite and modified wollastonite-reinforced poly(ether ether ketone) (PEEK) composites were prepared by melt blending. The mechanical properties, rheology behavior, and thermal properties of the composites were investigated. The modified wollastonite-reinforced PEEK composites exhibited better mechanical properties than the unmodified wollastonite-reinforced PEEK composites based on good interfacial adhesion. The composites had lower activation volume and complex shear viscosity. Furthermore, the modified wollastonite-reinforced PEEK composites had higher crystallization peak temperature ([T.sub.c]) and crystalline fraction ([χ.sub.c]) compared with the unmodified wollastonite-reinforced PEEK composites. This study shows that the traditional silane coupling agents could effectively improve the performance of PEEK composites. POLYM. ENG. SCI., 51:1051-1058, 2011. [C]2011 Society of Plastics Engineers, INTRODUCTION Poly(ether ether ketone) (PEEK) is a kind of semicrystalline thermoplastic polymer with outstanding performance such as high temperature resistance, excellent chemical resistance, and superior mechanical properties [1, 2]. To [...]

Nanocomposites of Sulfonated Poly(Aryl ether ketone) (SPAEK) and functional multiwall carbon nanotubes (a-MWNTs) were fabricated by a solution method. The results showed that the composites exhibited a higher dielectric constant that was near 600 when the volume fraction of carbon-nanotubes was 0.07 (7 vol%) at 103 Hz. The percolation threshold of the a-MWNTs/SPAEK composites was only 3 vol% of a-MWNTs, and the dielectric constant could reach 210. The dielectric constant of composites changed little with frequency increase when the content of carbon nanotubes was more than 3 vol%, and the composites could keep high dielectric constant at high-frequency (>200, at 106 Hz). [ABSTRACT FROM AUTHOR]

Magnetite (Fe 3 O 4 ) has a large theoretical reversible capacity and rich Earth abundance, making it a promising anode material for LIBs. However, it suffers from drastic volume changes during the lithiation process, which lead to poor cycle stability and low-rate performance. Hence, there is an urgent need for a solution to address the issue of volume expansion. Taking inspiration from how glycophyte cells mitigate excessive water uptake/loss through their cell wall to preserve the structural integrity of cells, we designed Fe 3 O 4 @PMMA multi-core capsules by microemulsion polymerization as a kind of anode materials, also proposed a new evaluation method for real-time repair effect of the battery capacity. The Fe 3 O 4 @PMMA anode shows a high reversible specific capacity (858.0 mAh g -1 at 0.1 C after 300 cycles) and an excellent cycle stability (450.99 mAh g -1 at 0.5 C after 450 cycles). Furthermore, the LiNi 0.8 Co 0.1 Mn 0.1 O 2 /Fe 3 O 4 @PMMA pouch cells exhibit a stable capacity (200.6 mAh) and high-capacity retention rate (95.5 %) after 450 cycles at 0.5 C. Compared to the original battery, the capacity repair rate of this battery is as high as 93.4 %. This kind of bionic capsules provide an innovative solution for improving the electrochemical performance of Fe 3 O 4 anodes to promote their industrial applications., (© 2024 Wiley-VCH GmbH.)