We report a solvent-free dry powder coating process for making LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC) positive electrodes in lithium-ion batteries. This process eliminates volatile organic compound emission and reduces thermal curing time from hours to minutes. A mixture of NMC, carbon black, and poly(vinylidene difluoride) was electrostatically sprayed onto an aluminum current collector, forming a uniformly distributed electrode with controllable thickness and porosity. Charge/discharge cycling of the dry-powder-coated electrodes in lithium-ion half cells yielded a discharge specific capacity of 155 mAh g -1 and capacity retention of 80% for more than 300 cycles when the electrodes were tested between 3.0 and 4.3 V at arate of C/5. The long-term cycling performance and durability of dry-powder coated electrodes are similar to those made bythe conventional wet slurry-based method.This solvent-free dry powder coating process is a potentially lower-cost, higher-throughput, and more environmentally friendly manufacturing process compared with the conventional wet slurry-based electrode manufacturing method.

Because of its natural abundance and high theoretical specific capacity (3579 mAh g, based on LiSi), silicon and its composites have been extensively studied as the negative electrode for future high energy density lithium-ion batteries. While rapid failure due to the significant volumetric strain of lithium-silicon reactions makes bulk silicon unsuitable for practical applications, silicon nanoparticles can sustain the large volume changes without fracturing. However, polymeric binders are usually required to maintain the structural integrity of electrodes made of particles. Recent lithium-ion half-cell tests have shown that lithium ion-exchanged Nafion (designated as Li-Nafion) and sodium alginate are highly promising binders for nanoparticle silicon electrodes. Nevertheless, there is scant information on the performance and durability of these electrodes in full cell tests which are likely to reveal the role of binders under more realistic conditions. This work focuses on understanding the role of various binders in lithium-ion full cells consisting of Si negative electrode and LiNiMnCoO positive electrode. This study demonstrates, possibly for the first time, that silicon nanoparticles with either Li-Nafion or sodium alginate as binder can maintain a constant capacity of 1200 mAh g for more than 100 cycles. In addition, during deep charge/discharge cycling, silicon electrodes containing Li-Nafion, Nafion, and sodium alginate can exhibit better capacity retention and higher specific capacity than that of silicon electrodes using polyvinylidene fluoride (PVDF) as a binder.

This work demonstrates a high-performance and durable silicon nanoparticle-based negative electrode in which conventional polymer binder and carbon black additive are replaced with lignin. The mixture of silicon nanoparticles and lignin, a low cost, renewable, and widely available biopolymer, was coated on a copper substrate using the conventional slurry mixing and coating method and subsequently heat-treated to form the composite electrode. The composite electrode showed excellent electrochemical performance with an initial discharge capacity of up to 3086 mAh g and retaining 2378 mAh g after 100 cycles at 1 A g. Even at a relatively high areal loading of ∼1 mg cm, an areal capacity of ∼2 mAh cm was achieved. The composite electrode also displayed excellent rate capability and performance in a full-cell setup. Through synergistic analysis of X-ray photoelectron spectroscopy, Raman, and nanoindentation experiment results, we attribute the amazing properties of Si/lignin electrodes to the judicious choice of heat treatment temperature at 600 °C. At this temperature, lignin undergoes complex compositional change during which a balance between development of conductivity and retaining of polymer flexibility is realized. We hope this work could lead to practicable silicon-based negative electrodes and stimulate the interest in the utilization of biorenewable resources in advanced energy applications.

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This work aims preparation of polymer-based biocomposite coating by electrostatic spray method onto 316L stainless steel substrate, the present work will compare the effects of incorporation of Al2O3 and TiO2 particles at a different percentage of (10,15 and 20 % wt. from Al2O3 and TiO2 with (90,85 and 80% wt. PMMA - based electrostatic deposition coating is studied. The structure and chemical composition of composite coatings were studied by using (SEM) & (EDS) and mechanical properties (Microhardness and adhesion strength) of Al2O3-TiO2-PMMA composite coating. The SEM&EDX result showed that the composite coating to be dense with uniform dispersants and continuous with a well homogenous mixture within coating exhibits a much-increased Microhardness and remarkably improved adhesion strength.