NixSi1-x (0 ≤ x ≤ 0.5, Δx = 0.05) alloys were prepared by ball milling and studied as anode materials for lithium ion batteries. Nanocrystalline Si/NiSi2 phases were formed for x ≤ 0.25. The NiSi phase was observed for samples with higher Ni content. Increasing the Ni content was found to gradually lower the lithiation voltage, while delithiation voltage was not affected for x ≤ 0.25. As a result, Li15Si4 did not form during cycling for x > 0.15. The capacity trend of NixSi1-x alloys with composition suggested that the nanocrystalline NiSi2 phase had some activity toward Li, while the NiSi phase had no capacity toward Li. In situ XRD studies confirmed the activity of nanocrystalline NiSi2. The best cycling performance of NixSi1-x alloys was obtained for x = 0.20 with 94% capacity retention after 50 cycles.

The structure and electrochemistry in lithium cells of sputtered thin films and ball milled alloys in the Cu-Si system (0 ≤ x ≤ 0.60 in CuxSi1−x) were investigated. Both thin films and ball milled Cu-Si alloys showed the co-existence of amorphous Si and a nanocrystalline Cu3Si phase. The lithiation potential of Cu-Si alloys was found to be significantly shifted to potentials below that of pure Si. In addition, the Cu3Si phase was found to be involved in the electrochemical reaction of the alloys with lithium, however not all of the Si could be reacted with Li to its full theoretical extent. This suggests that a ternary Cu-Li-Si phase may be formed at full lithiation of these alloys.

CO2-responsive polymers with high nitrogen to carbon ratios were tested as potential forward osmosis draw solutes in a forward osmosis/ultrafiltration process. Aqueous solutions of these polymers have the potential to produce high osmotic pressures in the presence of CO2 (up to 67 bar) but exhibit dramatically lower osmotic pressures under air. Purifying the polymer by dialysis to remove lower molecular mass materials significantly reduces the osmotic pressure under air without greatly lowering the osmotic pressure under CO2.

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CO 2 -responsive branched poly(N,N-dimethylallylamine) (b-PDMAAm) was evaluated as a potential draw solute for forward osmosis. PDMAAm with different degrees of branching was synthesized to investigate the effect of branching on the properties of branched polymeric draw solutes compared to their linear counterparts. Since molecular architecture can significantly affect the rheological properties of polymer solutions, b-PDMAAm was expected to have lower aqueous solution viscosity than linear PDMAAm of the same molecular weight, but the results surprisingly showed that the solution viscosities were similar. Branched CO 2 -responsive PDMAAm exhibited high osmotic pressures in the presence of CO 2 and low osmotic pressures in air; however, osmotic pressures in both the protonated and neutral states were lower than those for linear PDMAAm. Moreover, the osmotic pressure of PDMAAm decreased with increasing branching degree. The dependence of osmotic pressure of PDMAAm (5− 40 wt %) on its topology was further studied by 1 H NMR relaxation measurements.