Electrodes composed of silicon nanoparticles (SiNP) were prepared by slurry casting and then electrochemically tested in a fluoroethylene carbonate (FEC)-based electrolyte. The capacity retention after cycling was significantly improved compared to electrodes cycled in a traditional ethylene carbonate (EC)-based electrolyte.

Solution-grown germanium (Ge) nanowires were tested as high capacity anodes in lithium ion (Li-ion) batteries. Nanowire films were formulated and cast as slurries with conductive carbon (7:1 Ge:C w/w), PVdF binder and 1.0 M LiPF(6) dissolved in various solvents as electrolyte. The addition of fluorethylene carbonate (FEC) to the electrolyte was critical to achieving stable battery cycling and reversible capacities as high as 1248 mA h g(-1) after 100 cycles, which is close to the theoretical capacity of 1,384 mA h g(-1). Ge nanowire anodes also exhibited high rate capability, with reversible cycling above 600 mA h g(-1) for 1200 cycles at a rate of 1C. The batteries could also be discharged at 10C with a capacity of 900 mA h g(-1) when charged at 1C.

Conformal Al2O3 coating improves wettability of liquid electrolyte on lithium leading to homogenous electrodeposition, reduced dendrite growth, and improved cyclability.

A tin (Sn)-seeded supercritical fluid−liquid−solid (SFLS) synthesis of silicon (Si) nanowires with trisilane reactant was developed. When used as anodes in lithium ion (Li-ion) batteries, films of the nanowires with poly(vinylidene) fluoride (PVdF) or sodium alginate (NaAlg) binder, carbon conductor, and fluoroethylene carbonate (FEC)-containing electrolyte gave reversible, high charge storage capacities of 1,800 mA h g −1 . The nanowires also exhibited relatively good rate capability, with capacities of 400 mA h g −1 at the relatively fast cycling rates of 2C.

The effects of binder, electrolyte, and presence of gold (Au) seeds on the performance of silicon (Si) nanowire anodes in Lithium (Li)-ion batteries were systematically examined. Large irreversible capacity loss, poor performance at cycle rates of C/5 and faster, and significant capacity fade were observed when excess Au was not removed from the Si nanowires. Battery stability was very poor when poly (vinylidene fluoride) (PVdF) binder and common carbonate electrolytes, ethylene carbonate, dimethyl carbonate, and diethyl carbonate were used. Respectable Li-ion battery performance was obtained with sodium alginate binder and fluoroethylene carbonate (FEC) added to the electrolyte, with capacities up to 2000 mA h g–1 after the first 100 cycles.

No abstract

Adding 10 mM KPF6 to the 1 M LiPF6 in ethylene carbonate/dimethyl carbonate electrolyte of symmetrical Li | Li cells eliminated the growth of dendrites at 0.5 mA cm–2 current density and massively reduced, but did not eliminate, the growth of dendrites at 2.5 mA cm–2. The added KPF6 increased the fraction of inorganic salts in the solid electrolyte interface, making it thinner and more Li+ conductive. It overcame the growth of dendrites resulting from inadequate nucleation density but not dendrite growth into the depletion layer, which scales with the layer’s thickness, i.e., the current density.

Lithium metal is considered the "holy grail" of next-generation battery anodes. However, severe parasitic reactions at the lithium-electrolyte interface deplete the liquid electrolyte and the uncontrolled formation of high surface area and dendritic lithium during cycling causes rapid capacity fading and battery failure. Engineering a dendrite-free lithium metal anode is therefore critical for the development of long-life batteries using lithium anodes. In this study, we deposit a conformal, organic/inorganic hybrid coating, for the first time, directly on lithium metal using molecular layer deposition (MLD) to alleviate these problems. This hybrid organic/inorganic film with high cross-linking structure can stabilize lithium against dendrite growth and minimize side reactions, as indicated by scanning electron microscopy. We discovered that the alucone coating yielded several times longer cycle life at high current rates compared to the uncoated lithium and achieved a steady Coulombic efficiency of 99.5%, demonstrating that the highly cross-linking structured material with great mechanical properties and good flexibility can effectively suppress dendrite formation. The protected Li was further evaluated in lithium-sulfur (Li-S) batteries with a high sulfur mass loading of ∼5 mg/cm. After 140 cycles at a high current rate of ∼1 mA/cm, alucone-coated Li-S batteries delivered a capacity of 657.7 mAh/g, 39.5% better than that of a bare lithium-sulfur battery. These findings suggest that flexible coating with high cross-linking structure by MLD is effective to enable lithium protection and offers a very promising avenue for improved performance in the real applications of Li-S batteries.