Unique Core–Shell Nanorod Arrays with Polyaniline Deposited into Mesoporous NiCo₂O₄ Support for High-Performance Supercapacitor Electrodes

Polyaniline (PANI), one of the most attractive conducting polymers for supercapacitors, demonstrates a great potential as high performance pseudocapacitor materials. However, the poor cycle life owing to structural instability remains as the major hurdle for its practical application; hence, making the structure-to-performance design on the PANI-based supercapacitors is highly desirable. In this work, unique core–shell NiCo₂O₄@PANI nanorod arrays (NRAs) are rationally designed and employed as the electrode material for supercapacitors. With highly porous NiCo₂O₄ as the conductive core and strain buffer support and nanoscale PANI layer as the electrochemically active component, such a heterostructure achieves favorably high capacitance while maintaining good cycling stability and rate capability. By adopting the optimally uniform and intimate coating of PANI, the fabricated electrode exhibits a high specific capacitance of 901 F g^–1 at 1 A g^–1 in 1 M H₂SO₄ electrolyte and outstanding capacitance retention of ∼91% after 3000 cycles at a high current density of 10 A g^–1, which is superior to the electrochemical performance of most reported PANI-based pseudocapacitors in literature. The enhanced electrochemical performance demonstrates the complementary contributions of both componential structures in the hybrid electrode design. Also, this work propels a new direction of utilizing porous matrix as the highly effective support for polymers toward efficient energy storage

Spatial location of weedy rice populations used for outcrossing and genetic diversity studies.

<p>The HLJ-1 to HLJ-4 populations were collected from Heilongjiang Province; the JL-1 to JL-4 populations from Jilin Province; and the JS-1 to JS-4 populations from Jiangsu Province. The detail information of each population refers to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0016189#pone-0016189-t001" target="_blank">Table 1</a>.</p

Paternal specific alleles and their frequencies in weedy rice populations as estimated by MLRT (Ritland, 2002) [36].

<p>The shared alleles detected in rice varieties grown in the same field were indicated in the last column.</p><p>*The crop-specific alleles.</p

SSR primer pairs used for DNA amplification with their molecular weight of fragments detected in eleven weedy rice populations.

<p>*Primer pairs with <u>underlines</u> were used in diversity analysis; primer pairs with <b>Bold</b> letters were used in outcrossing of weedy rice and crop-specific allele analysis; primer pairs with <u>underlined</u><b>Bold</b> letters were used for cluster analysis of weedy and cultivated rice.</p

Outcrossing rates of eleven weedy rice populations estimated using the multilocus mixed mating model.

<p><i>t_m</i>: outcrossing rate estimated by multiple loci; <i>t_s</i>: outcrossing rate estimated by single loci; (<i>t_m</i> - <i>t_s</i>_)/<i>t_m</i>: the proportion of the biparental inbreeding to the total outcrossing (%); <i>Pa</i>: number of pollen donator parents (effective paternity); <i>Subs</i>: substructure estimated by difference of multilocus outcrossed paternity correlation and single-locus outcrossed paternity correlation. Numbers in parentheses indicate standard deviations (s.d.).</p

Parameters of genetic diversity in eleven weedy rice populations based on 22 SSR primer pairs.

<p><i>F_is</i>: Wright's (1978) inbreeding coefficient <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0016189#pone.0016189-Wright2" target="_blank">[40]</a>; <i>A</i>: average number of alleles per locus; <i>P</i>: percentage of polymorphic loci; <i>GD</i>: Nei's genetic diversity <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0016189#pone.0016189-Nei1" target="_blank">[41]</a>; <i>H_o</i>: observed heterozygosity. Numbers in parentheses indicate standard deviations (s.d.).</p

The inbreeding coefficients (<i>f_M</i>) of maternal plants plotted as a function of outcrossing rates (<i>t_m</i>).

<p>Bars indicate the standard deviation of the means. Expected inbreeding coefficients at inbreeding equilibrium (<i>f_eq</i>), calculated by (1 - <i>t_m</i>)/(1+<i>t_m</i>), is plotted in a bold line.</p

The UPGMA dendrogram of weedy rice populations, based on Nei's unbiased genetic distance.

<p>The numbers on the branches indicate the percentages of times a cluster appeared in 1000 bootstrap samples.</p

Sampling and location of weedy rice populations and the coexisting rice cultivars from northeast and east China for the estimate of outcrossing rates and genetic diversity.

<p>*Numbers in parentheses indicate the numbers of progeny.</p><p>**Code is included in parentheses.</p

The UPGMA dendrogram of weedy rice populations and the coexisting rice varieties in the same fields, based on Nei's unbiased genetic distance of 4 shared SSR primer pairs (RM21, RM218, RM219, RM276) by the two taxa.

<p>The UPGMA dendrogram of weedy rice populations and the coexisting rice varieties in the same fields, based on Nei's unbiased genetic distance of 4 shared SSR primer pairs (RM21, RM218, RM219, RM276) by the two taxa.</p