In the present work nanostructures of manganese dioxide have been synthesized and characterized as potential catalysts for Li-air batteries. The R-MnO2 nanourchin-shaped catalyst was synthesized by mild hydrothermal conditions under autogeneous pressure. X-ray powder diffraction (XRD) was used to confirm the formation of single R-MnO2. The microstructure of the obtained nanostructures was investigated by scanning and transmission electron microscopy (SEM and TEM) showing the presence of acicular manganese oxide aggregates (5-10 nm wide) which tend to form spherical clusters, taking on an urchin-shaped form of roughly 6 microns diameter. The cyclability analyses reveal an enhanced performance and efficiency for the batteries with higher amounts of catalyst. This catalyst is thought to promote alternative reaction pathways in the Li2CO3 decomposition which attenuate the instability of the electrolyte and/or carbon electrode during the discharge resulting in an improved cyclability.

Recent experimental evidence on nano-particle and nano-wire silicon anodes showed an initial rapid velocity of reaction front at the initial stage of lithiation, followed by an apparent slowing or even halting of the reaction front propagation. This intriguing phenomenon is attributed to the lithiation-induced mechanical stresses across the reaction front which is believed to play an important role in the kinetics of reaction at the front. Here, through theoretical formulation, we presented a comprehensive study on lithiation-induced stress field and its contribution to the driving force of lithiation in hollow spherical anodes with different boundary conditions at the inner surface of the particle. Our results reveal that hollow spherical silicon anodes can be lithiated more easily than solid spherical silicon particles and thus may serve as an optimal design of high performance anodes of lithium-ion battery.

Three types of silica materials with different morphology, specifically SiO2 hollow microspheres, mesoporous silica, and silica aerogel were tested as potential precursors for synthesis of silicon nano- and meso-structures that resemble the original morphology of the precursors. In the optimized magnesium thermal reduction process, magnesium vapor was delivered to silica surface through a stainless steel mesh placed on top of a zirconia boat filled with silica precursor. This approach allowed for better control of silicon nanostructure formation by minimizing reaction by-products that can affect performance of lithium ion battery anode. Material morphological properties of the reduced silica precursors are discussed in terms of X-ray diffraction, BET, BJH pore size distribution, Raman spectroscopy, and TGA.

Silicon is emerging as a very attractive anode material for lithium ion batteries due to its low discharge potential, natural abundance, and high theoretical capacity of 4200 mAh/g, more than ten times that of graphite (372 mAh/g). This high charge capacity is the result of silicon’s ability to incorporate 4.4 lithium atoms per silicon atom; however, the incorporation of lithium also leads to a 300-400% volume expansion during charging, which can cause pulverization of the material and loss of access to the silicon. The architecture of the anode must therefore be able to adapt to this volume increase. Here we present a layered carbon nanotube and silicon nanoparticle electrode structure, fabricated using directed assembly techniques. The porous carbon nanotube layers maintain electrical connectivity through the active material and increase the surface area of the current collector. Using this architecture, we obtain an initial capacity in excess of 4000 mAh/g, as well as increased power and energy density as compared to anodes fabricated using the standard procedure of slurry casting.

We discuss the advantages of V2O5-P2O5-Fe2O3-Li2O glass-ceramics as a cathode for lithium-ion batteries. The glass was prepared by using the melt quenching method. The glass-ceramics were produced by heat treatment in air. LixV2O5 crystal was only confirmed as the precipitated phase and the degree of crystallinity was approximately 90%. The total capacity of the glass-ceramics was 340 Ah/kg at a C/20 rate for 1.5-4.2 V cutoff ranges. It is 10% higher than the capacity of the glass cathode. Moreover, the charge-discharge performance of the glass-ceramics cathode showed good cycleability similar to that of the glass. The glass-ceramics had a 83% capacity retention after 40 cycles. These results show that glass-ceramics is a potential candidate for lithium-ion cathode materials.

Dense thin β/β’’-alumina electrolyte films of less than 50 μm thickness were fabricated using vacuum dip-coating on porous substrate tubes. The porous substrate tubes were fabricated using a slip casting method. Fine Na-β/β’’-alumina powder was obtained via traditional solid state reaction processing. It was found that vacuum dip-coating is an effective method for fabricating thin dense layers coated on the porous tube. The mechanical properties of the porous tube, with and without the dense layer, were tested using a C-ring method. The optimized sintering process was also studied.