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

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

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

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