The use of nanocarriers in biology and medicine is complicated by the current need to understand how nanoparticles interact in complex biological surroundings. When nanocarriers come into contact with serum, proteins immediately adsorb onto their surface, forming a protein corona which defines their biological identity. Although the composition of the protein corona has been widely determined by proteomics, its morphology still remains unclear. In this study we show for the first time the morphology of the protein corona using transmission electron microscopy. We are able to demonstrate that the protein corona is not, as commonly supposed, a dense, layered shell coating the nanoparticle, but an undefined, loose network of proteins. Additionally, we are now able to visualize and discriminate between the soft and hard corona using centrifugation-based separation techniques together with proteomic characterization. The protein composition of the ∼15 nm hard corona strongly depends on the surface chemistry of the respective nanomaterial, thus further affecting cellular uptake and intracellular trafficking. Large diameter protein corona resulting from pre-incubation with soft corona or Apo-A1 inhibits cellular uptake, confirming the stealth-effect mechanism. In summary, the knowledge on protein corona formation, composition and morphology is essential to design therapeutic effective nanoparticle systems.

Chemical irregularities such as side chain branches or comonomers in an otherwise regular polymer influence its crystallization. In most polymer systems, these chemical defects are randomly distributed along the chain, and it is difficult to understand in detail their effect on crystallization. We have examined three precision polymers prepared by acyclic diene metathesis (ADMET) polymerization. This synthesis ensures exact placement of the chain defects; here they are all separated by 20 CH2 units. The polymers are two polyphosphoesters with a phosphate or phosphonate group in the main chain and one polyethylene with butyl branches. Although the alkyl part is identical for all three polymers, their thermal and crystal properties differ noticeably. By means of differential scanning calorimetry, X-ray scattering, and transmission electron microscopy, we characterize the lamellar crystals and correlate our findings to the observed difference in thermal behavior.

A monoclinic lithium vanadium phosphate (Li3V2(PO4)3) and carbon composite thin film (LVP/C) is prepared via electrostatic spray deposition. The film is studied with X-ray diffraction, scanning and transmission electron microscopy and galvanostatic cell cycling. The LVP/C film is composed of carbon-coated Li3V2(PO4)3 nanoparticles (50 nm) that are well distributed in a carbon matrix. In the voltage range of 3.0–4.3 V, it exhibits a reversible capacity of 118 mA h g−1 and good capacity retention at the current rate of 1 C, while delivers 80 mA h g−1 at 24 C. These results suggest a practical strategy to develop new cathode materials for high power lithium-ion batteries.

Silicon working as anode for Li-ion batteries has attracted much attention due to its high capacity (∼4200 mAh g−1). However, due to the large volume expansion during lithiation, the capacity of silicon fades very fast. In this systematic study, we focus on the issue to fight the capacity fading. Results show that Si with sodium carboxymethyl cellulose (Na-CMC) as a polymer binder exhibits a better cyclability than that with poly(vinylidene fluoride) (PVDF). Yet differing from the system used in PVDF, the addition of vinylene carbonate (VC) does not improve or even worsens the performance of the system using Na-CMC. In addition, the small particle size of Si, a large amount of carbon black (CB), the good choice of electrolyte/conducting salt and charge–discharge window also play important roles to enhance the cyclability of Si. It is found that electrode consisting of 40 wt.% nano-Si, 40 wt.% carbon black and 20 wt.% Na-CMC (pH 3.5) displays the best cyclability, and in the voltage range from 0 to 0.8 V, after 200 cycles, its capacity can still keep 738 mAh g−1 (C/2, in 1 M LiPF6 ethylene carbonate/diethyl carbonate electrolyte, with VC-free), almost twice as that of graphite.

V2O5 nanofibers and three vanadium-based oxides with different structures (MnV2O6 nanosheets, FeVO4·0.92H2O nanoneedles, and Sn2VO6·0.78H2O nanoparticles) were synthesized via a hydrothermal method. Field-emission scanning electron microscopy, transmission electron microscopy, electron diffraction, energy dispersive X-ray, and electron energy loss spectroscopy were employed to characterize their morphologies and crystal structures. Electrochemical tests in rechargeable lithium batteries show that among these vanadium-based oxides Sn2VO6·0.78H2O nanoparticles exhibit the highest capacity, more than 1700 mAh g−1, and can keep good capacity retention. The magnetic properties of MnV2O6 nanosheets and FeVO4·0.92H2O nanoneedles were also investigated.

The diffusion coefficients of lithium ions (DLi+) in nano-Si were determined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT). DLi+ values are estimated to be ~ 10− 12 cm2 s− 1 and exhibit a “W” type varying with the lithium concentration in silicon. Two minimum regions of DLi+ (at Li2.1 ± 0.2Si and Li3.2 ± 0.2Si) are found, which probably result from two amorphous compositions (a-Li7Si3 and a-Li13Si4). Besides the two minimum regions, one maximum DLi+ is observed at Li15Si4, corresponding to the crystallization of highly lithiated amorphous LixSi.