Revealing the Intrinsic Li Mobility in the Li₂MnO₃ Lithium-Excess Material

One of the most promising avenues for future high energy Li-ion batteries originate from the family of Li-rich layered cathodes. However, while exhibiting excellent initial capacity, these materials also suffer from voltage fade, high impedance, and poor rate capability, particularly in the Mn-rich, high Li excess concentration regime. Though it is clear that the Li₂MnO₃ component contributes to the high capacity as well as the chemical and structural degradation of the material, the inherent ionic conductivity of the material has not been clarified. In this work, we investigate the delithiation mechanism, involving coherent Li migration from two layers by first-principles density functional theory. Surprisingly, and contrary to expectations from available experimental results, we find that the pristine material exhibits excellent Li mobility enabling facile Li extraction from both the transition metal layer and Li-layer. Generally, the Li-extractions are highly accelerated by di- and trivacancy clusters, which stabilize the saddle point tetrahedral sites. Hence, we deduce that the observed inferior rate behavior of this class of Li cathode materials is not due to intrinsic poor bulk ionic mobility, but more likely due to surface-passivation, structural deterioration, and/or particle–particle electrode-level transport limitations

Preparation of Polymer@AuNPs with Droplets Approach for Sensing Serum Copper Ions

A microfluidic droplet synthesis approach for the preparation of poly <i>N</i>-isopropylacrylamide protected gold nanoparticles (PNIPAm@AuNPs) was presented here. Well-dispersed PNIPAm@AuNPs could be generated within 8 min. On the basis of the aggregation-induced UV–vis adsorption intensity increasing mechanism, the PNIPAm@AuNPs-based colorimetric probe displayed high sensitivity and good selectivity for sensing copper ions. A linear calibration of relative UV–vis adsorption intensity increasing versus copper ions concentration was obtained within 5.0–750.0 μM, and the limit of detection was 2.5 μM. Furthermore, after copper ions were injected in rat, a metabolic assay was developed with the proposed probe. The results indicated that the droplet microfluidic synthesis system could provide a new way for preparation of polymer@AuNPs with good polydispersity index and showed great potential of polymer@AuNPs-based sensing probe for application in biological and clinical analysis

Evolution of cooperation frequency <i>ρ</i>_<i>c</i> (the left), average reputation (the center) and relevant average payoff (the right) of all population when <i>r</i> = 2.

<p>The other parameter settings are <i>θ</i> = 20, <i>K</i> = 0.5 and <i>μ</i> = 10⁻⁴.</p

Cooperation frequency <i>ρ</i>_<i>c</i> with <i>r</i> = 2.5.

<p>Every colored solid line describes the evolution of the frequency of cooperators in 1,000 generations. Of the six reputation tolerance levels, <i>T</i> = 3 and 4 resulted in high cooperation. The other parameter settings are <i>θ</i> = 20, <i>K</i> = 0.5 and <i>μ</i> = 10⁻⁴.</p

Cooperation frequency <i>ρ</i>_<i>c</i>, as a function of <i>T</i> for different values of <i>r</i>.

<p>Each data point resulted from average value of the frequency of the proportion of cooperators for the last 100 rounds after reaching steady state. The other parameter settings are <i>θ</i> = 20, <i>K</i> = 0.5 and <i>μ</i> = 10⁻⁴.</p

Cooperation frequency <i>ρ</i>_<i>c</i> acts as a function of <i>r</i> for different reputation tolerance <i>T</i>.

<p>Each data point results from the average value of the proportion of cooperators for the last 100 rounds after reaching steady state. The other parameter settings are <i>θ</i> = 20, <i>K</i> = 0.5 and <i>μ</i> = 10⁻⁴.</p

Cooperation frequency <i>ρ</i>_<i>c</i> as a function of <i>r</i> for different selection force <i>K</i>.

<p>The other parameter settings are <i>T</i> = 3, <i>θ</i> = 20 and <i>μ</i> = 10⁻⁴.</p

Evolutionary dynamics of cooperation frequency for different values of maximum reputation <i>θ</i> when <i>T</i> = 3 and <i>r</i> = 2.

<p>The other parameter settings are <i>K</i> = 0.5 and <i>μ</i> = 10⁻⁴.</p

The outcome of the univariate analysis of variance between the two surveys.

<p>Adjusted age, Educational background, Professional titles, Tenure (years), R Squared =0.014 (Adjusted R Squared =0.010)</p

Evolutionary dynamics of cooperation frequency under different initial settings.

<p>The two blue lines show the results when <i>r</i> = 3 and <i>T</i> = 3; the two reds lines show the results when <i>r</i> = 3.5 and <i>T</i> = 1; and the two yellow lines shown the results when <i>r</i> = 3 and <i>T</i> = 2. For darker colored lines, all individuals’ initial reputation values are set to be 0, while for lighter colored lines, individuals’ initial reputation values are randomly selected from [0, <i>θ</i>]. The other parameter settings are <i>θ</i> = 20, <i>K</i> = 0.5 and <i>μ</i> = 10⁻⁴.</p