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The porous structure composed of non-metal elements of covalent organic frameworks (COFs) contributes to a large surface area and multifunction, rendering COFs a brilliant material for energy storage. Unfortunately, the low conductivity of most COFs limits their application in batteries. Herein, we fabricate COF-derived nitrogen-doped porous carbon (NPC) using nitrogen-rich COF-JLU2 as precursors by a simple carbonization for potassium-ion batteries (PIBs) and aluminum (Al) batteries for the first time. The computational results suggest that NPC has an enhanced conductivity and optimized electron density distribution. NPC could overcome the low conductivity of COF and thus further optimize its electrochemical performance in PIBs and Al batteries. It displays an excellent stability even after 2500 cycles (as the anode for PIBs) and 30000 cycles (as the cathode for Al batteries) with a high Coulombic efficiency. This fascinating study may be extended in other COFs for energy storage applications.

Potassium has similar chemical characteristics compared with lithium while it is more abundant and of low cost, resulting in widespread research attention on potassium-ion batteries (PIBs). Developing organic polymer cathodes has garnered extensive attention because of their merits of environmental friendship and structure diversity, while confronted with inferior cycle stability and low rate performance. In this paper, we utilize the low-cost graphite nanosheets to stabilize polyimide (PI@G) for PIBs. Additionally, the potassium storage mechanism of PI@G was further evaluated; the highly reversible chemical bonds (C═O) of PI@G are responsible to its long-term stability. Consequently, the PI@G exhibits a maximal capacity of 142 mA h g-1 at the current density of 100 mA g-1 and maintains a capacity of 118 mA h g-1 after 500 cycles (corresponding to a capacity fade of 0.034% per cycle). Moreover, the full battery based on the PI@G cathode also reveals promisingly electrochemical performance. This study may have great significance to the application prospect of the organic cathode for PIBs.

Graphene is of great significance in energy storage devices. However, a graphene-based electrode is difficult to use in direct applications due to the large surface area and flexibility, which leads to the excessive consumption of electrolyte, low Coulombic efficiency, and electrode shedding behaviors. Herein, a special crystal carbon@graphene microsphere (CCGM) composite was successfully synthesized. The scalable carbonaceous microsphere composite displays a small specific surface area and a superior structure stability. As a potassium ion battery electrode in a half-cell, CCGM delivers an initial capacity of 297.89 mAh g

To acquire remarkable cathode materials for lithium-sulfur batteries with ultrahigh utilization of active materials and superior cycling stability, we firstly employ carboxylated carbon nanotubes to prepare the NiCo2S4@CNTs/S for lithium-sulfur batteries via a simple hydrothermal method, following by a low temperature annealing. The NiCo2S4@CNTs presents a unique structure, which possesses thin branches filled with densely packed small leaves where a large number of micropores distribute. In the novel superstructure, carboxylated carbon nanotubes can effectively improve the electronic transportation capacity and conductivity of the cathode material. In lithium-sulfur batteries, bimetal sulfides have a strong adsorption of the polysulfides, effectively suppressing the diffusion of lithium polysulfides. The NiCo2S4@CNTs/S electrode shows a capacity of 788 mA h g−1 at the current density of 0.5 C and 758 mA h g−1 at 2 C. Even after 1000 cycles at the current density of 0.6 C the capacity only decays by 0.0489% each cycle. It should be notes that most of Coulombic efficiency of the NiCo2S4@CNTs/S electrode is about 99%, regardless of the current density. More importantly, the NiCo2S4@CNTs can exhibit an outstanding capability of absorbing lithium polysulfides, which provides a promising strategy for preparing advanced lithium-sulfur batteries.

Large-scale low-cost synthesis methods for potassium ion battery (PIB) anodes with long cycle life and high capacity have remained challenging. Here, inspired by the structure of a biological cell, biomimetic carbon cells (BCCs) were synthesized and used as PIB anodes. The protruding carbon nanotubes across the BCC wall mimicked the ion-transporting channels present in the cell membrane, and enhanced the rate performance of PIBs. In addition, the robust carbon shell of the BCC could protect its overall structure, and the open space inside the BCC could accommodate the volume changes caused by K+ insertion, which greatly improved the stability of PIBs. For the first time, a stable solid electrolyte interphase layer is formed on the surface of amorphous carbon. Collectively, the unique structural characteristics of the BCCs resulted in PIBs that showed a high reversible capacity (302 mAh g−1 at 100 mA g−1 and 248 mAh g−1 at 500 mA g−1), excellent cycle stability (reversible capacity of 226 mAh g−1 after 2100 cycles and a continuous running time of more than 15 months at a current density of 100 mA g−1), and an excellent rate performance (160 mAh g−1 at 1 A g−1). This study represents a new strategy for boosting battery performance, and could pave the way for the next generation of battery-powered applications., A potassium ion battery with biomimetic carbon cells as the anode exhibits high reversible capacity, excellent cycle stability (continuous running time of over 15 months) and excellent rate performance.

Lithium sulfur battery is considered one of the most promising rechargeable energy storage devices due to its ultrahigh theoretical energy density and specific capacity. It still cannot be applied because of some key problems. In particular, the shuttle effect of soluble polysulfide compounds leads to the rapid attenuation of battery capacity, short cycle life and serious self-discharge effect. TiO2 quantum dots and polysulfide compounds have strong interactions and can capture soluble polysulfide compounds, thus inhibiting the shuttle effect. Herein, we introduce a battery separator based on TiO2 quantum dots modified multi walled carbon nanotubes to solve the shuttle effect and adapt to the expansion of electrodes during charging and discharging. The interlayer has abundant spacing and excellent conductivity. This strategy can significantly improve the stability of lithium sulfur batteries. As a result, Li-S cells with MWCNTs@TiO2 quantum dots modified separator deliver an initial capacity of 1083 mAh g−1 and keep a cycle capacity of 610 mAh g−1 after 600 cycles at the rate of 838 mA g−1, which maintains an average capacity decay of only 0.072% per cycle. This simple and effective method can greatly improve the application capacity of lithium sulfur batteries.

Reasonable design of Sb-based nanomaterials, which can alleviate volume expansion, agglomeration and pulverization, is meaningful for PIBs. We used Sb-MOFs as precursors to perfectly and controllably embed uniform Sb nanoparticles (∼19 nm) into porous carbon networks through simple carbonization strategies and achieved excellent electrochemical performance for PIBs.

Rational regulation of phosphorus (P) use in the soil&ndash, rhizosphere&ndash, plant system is challenging in the development of sustainable, intensive, and healthy agriculture. Rational maize (Zea mays L.) based intercropping with legumes/oilseed rape across six experimental sites from 2008 to 2017 proved advantageous over monoculture in terms of both maize biomass production and P uptake. The partial land equivalent ratio (PLER) for P uptake by intercropped maize averaged from 0.58 to 0.92, which was significantly higher than that for biomass production (0.51&ndash, 0.78), indicating that the advantage of P acquisition by intercropped maize was superior to that of biomass accumulation. It was the excessive accumulation of P in intercropped maize compared to monoculture, especially higher P concentrations in grains that led to the superior P acquisition advantage and luxury absorption of P. P concentrations in maize grains were significantly increased from 1.89&ndash, 2.91 mg kg&minus, 1 in monoculture to 2.09&ndash, 3.65 mg kg&minus, 1, in intercropping, by 8.3%&ndash, 25.5%. The plant internal P use efficiency of maize was significantly decreased from the initial 411.7&ndash, 775.7 kg kg&minus, 1 in monoculture to 345.7&ndash, 710.4 kg kg&minus, 1 in intercropping by 4.9%&ndash, 16.0%, and 100 kg maize grain P quantities were significantly increased from 0.25&ndash, 0.46 kg to 0.27&ndash, 0.54 kg by 7.0%&ndash, 17.4%. Rational fertilizer P input maximized maize yields and P use without decreasing the interspecific ecological advantages and harvest indexes of grain yields and P. These findings promoted better understanding of P allocation status within maize plants, and yield and P acquisition advantages through the exploitation of the biological potential of plants for the efficient utilization of P resources in diverse species combinations.

Potassium‐ion batteries (KIBs) are one of the most appealing alternatives to lithium‐ion batteries, particularly attractive in large‐scale energy storage devices considering the more sufficient and lower cost supply of potassium resources in comparison with lithium. To achieve more competitive KIBs, it is necessary to search for anode materials with a high performance. Herein, the bimetallic oxide Sb2MoO6, with the presence of reduced graphene oxide, is reported as a high‐performance anode material for KIBs in this study, achieving discharge capacities as high as 402 mAh g−1 at 100 mA g−1 and 381 mAh g−1 at 200 mA g−1, and reserving a capacity of 247 mAh g−1 after 100 cycles at a current density of 500 mA g−1. Meanwhile, the potassiation/depotassiation mechanism of this material is probed in‐depth through the electrochemical characterization, operando X‐ray diffraction, transmission electron microscope, and density functional theory calculation, successfully unraveling the nature of the high‐performance anode and the functions of Sb and Mo in Sb2MoO6. More importantly, the phase development and bond breaking sequence of Sb2MoO6 are successfully identified, which is meaningful for the fundamental study of metal‐oxide based electrode materials for KIBs.

Tin and antimony with layered structure is proposed for the first time for the exceptional anode of potassium ion batteries (PIBs). The Sn-Sb with a layer structure significantly alleviates the structural damage and material pulverization caused by volume expansion during the reaction of potassium ions with metal atoms in the form of insertions, improving the cycling stability of PIBs. Owing to the unique structure, the material can achieve a high capacity of 296 mA h g−1 at 500 mA g−1 over 150 cycles, which maintains an average capacity decay of only 0.065% per cycle with Coulombic efficiency of 98%, and have low charge/discharge plateaus (less than 0.5 V). More importantly, the Sn-Sb material with layer structure can still provide a high capacity of 118 mA h g−1 at 5 A g−1 with Coulombic efficiency of 99%, which show high rate performance. This work not only solves the problem of rapidly decreasing capacity aroused by the volume expansion of antimony during charging and discharging, but also opens up a new idea about the application of metal material in PIBs.

Cathode materials with specific physicochemical properties are key to the excellent electrochemical performance of aluminum batteries. Here, we propose a catalyst-free microwave pulse radiation method to simply and rapidly convert Ketjen black into inter-connected carbon nanocage. The product has a three-dimensional inter-connected network framework, a large specific surface area, and eximious structural stability, which is beneficial for industrial development applications. Besides, molecular dynamics simulations show that when inter-connected carbon nanocage is used to AlCl4− anion storage, it has a self-protection mechanism, which can avoid structure collapse caused by excessive anion embedding. The inter-connected carbon nanocage exhibits excellent discharge capacity of 117 mAh g−1 at a current density of 1000 mA g−1 and exceptional stability with a discharge capacity as high as 105 mAh g−1 at 2000 mA g−1 after 1000 cycles as the cathode for the aluminum battery. The study greatly increases the production speed and reduces the requirements of experimental conditions for carbon nanocage, which may lead to a significant breakthrough for rapid, large-scale production of aluminum battery cathode materials and other fields.

This design provides a scalable route for in situ synthesizing of special carbon nanoscrolls as the cathode for an aluminum battery. The frizzy architectures are generated by a few graphene layers convoluting into the hollow carbon scroll, possessing rapid electronic transportation channels, superior anion storage capability, and outstanding ability of accommodating a large volume expansion during the cycling process. The electrochemical performance of the carbon nanoscroll cathode is fully tapped, displaying an excellent reversible discharge capacity of 104 mAh g–1 at 1000 mA g–1. After 55 000 cycles, this cathode retains a superior reversible specific capacity of 101.24 mAh g–1 at an ultrafast rate of 50 000 mA g–1, around 100% of the initial capacity, which demonstrates a superior electrochemical performance. In addition, anionic storage capability and structural stability are discussed in detail. The battery capacity under a wide temperature range from −80 to 120 °C is examined. At a low temperature o...

β-AgVO 3 nanorods have been successfully synthesized by a soft chemistry route, followed by calcination at different temperatures without templates. The crystallinity of the products increases with calcination temperatures. The β-AgVO 3 nanorods fabricated at 400 °C are very uniform and well-dispersed, with the diameter ranging from 70 nm to 300 nm, the length of which can be as long as several micrometres. The electrochemical measurements indicate that the β-AgVO 3 nanorods deliver high initial discharge capacities at various current densities and shows good rate capability. The superior electrochemical properties of β-AgVO 3 nanorods suggest they are promising cathode materials for implantable cardioverter defibrillators (ICDs).

Galvanic corrosion of a 6092-T6 Al metal-matrix composite (MMC) reinforced with boron carbide (B4C) particulates was examined through electrochemical characterization of the MMC as well as a monolithic B4C. The results were interpreted based on a recently proposed electronic model for B4C that emphasizes a conventional non-degenerate p-type semiconductor band structure with high density of gap states. A combination of scanning vibration electrode technique and scanning ion-selective electrode technique revealed that localized anodic and cathodic sites of over 200 μm in diameter co-existed on the surface of the MMC during immersion of the MMC in an air-exposed 3.15 wt% NaCl solution.

Corrosion morphologies of a 6092-T6 Al metal-matrix composite (MMC) reinforced with boron carbide (B4C) or silicon carbide (SiC) particulates as well as a Al-2%Cu alloy in solutions containing 1 mM Ni(NO3)2 or Co(NO3)2 were examined with scanning electron microscopy (SEM) and energy-dispersive X-ray analyses (EDXA). SEM indicated that precipitates formed on the surfaces of the MMCs and the Al-2%Cu alloy after prolonged immersion in the Ni(NO3)2 or Co(NO3)2 solutions. EDXA indicated that the precipitates contained Ni or Co elements. SEM also suggested that localized corrosion of the MMCs may be inhibited in the Ni(NO3)2 or Co(NO3)2 solutions without chloride ions but may be accelerated in the Ni(NO3)2 or Co(NO3)2 solutions added with chloride ions. X-ray diffraction (XRD) experiments suggested that the precipitates may be Al-Ni or Al-Co hydrotalcite-like compounds.

The corrosion rates of particulate 6092-T6 Al metal-matrix composites (MMCs) reinforced with 20 vol. % of B4C, SiC, and Al2O3 in ASTM seawater and real seawater were lower than those in 3.15 wt% NaCl or 0.5 M Na2SO4 solutions. Scanning electron microscopy revealed that precipitates consisting of agglomerated whiskers formed on the surfaces of the MMCs after prolonged immersion in either ASTM seawater or real seawater. The precipitates were tentatively ascribed to be Al-Mg hydrotalcite-like compounds based on energy-dispersive X-ray and X-ray diffraction analyses. Accordingly, the precipitation was proposed to follow an induced hydrolysis process that requires a relatively low pH close to that of seawater. It was postulated that the corrosion of the MMCs was inhibited both by precipitates that impede the diffusion of oxygen to cathodic sites and by the buffering effect of seawater, which attenuates pH fluctuations near the MMC surfaces.

Localized corrosion initiated on a 6092-T6 aluminum-based metal-matrix composite (MMC) reinforced with 20 vol.% SiC particles in an air-exposed 3.15 wt% NaCl solution. SEM indicated that corrosion initiated around SiC reinforcements. The polarization diagrams under illumination suggested that the SiC reinforcements were p-doped and that a semiconductor/electrolyte junction barrier existed. It was hypothesized that Al4C3 formed at the SiC-Al interface during the processing of the Al/SiC MMC. In the presence of water, the Al4C3 hydrolyzes and can induce crevices at the Al-SiC interfaces. Corrosion could thus initiate from these crevices. The scanning vibrating electrode technique revealed that the net currents over the localized corrosion region switched from anodic to cathodic, while the scanning ion-selective electrode technique revealed that the solution near the localized corrosion region switched from acidic to alkaline. The effects of solution pH on the local potential fluctuations of aluminum are believed to be related to this alternation.

Localized corrosion formed on an Al-based metal-matrix composite (MMC) reinforced with 40 wt% Si particles in an air-exposed 0.5 M Na2SO4 solution. Scanning vibrating electrode technique revealed that the net currents over the localized corrosion region were cathodic. Scanning ion-selective electrode technique revealed that the solution near the localized corrosion region was alkalized. Scanning electron microscopy indicated that corrosion initiated around Fe-containing intermetallic particles, which serve as cathodic sites. It is hypothesized that during the processing of the Al/Si MMC, inter-diffusion causes Al atoms to diffuse into Si particles forming a layer of highly p-doped Si at the Al/Si interface. Thus, following the immersion of the MMC into the Na2SO4 solution, at the sites adjacent to the Fe-containing intermetallic particles where the Al matrix dissolved, highly p-doped Si surfaces were exposed to the solution. The highly p-doped surfaces can therefore serve as cathodic sites and exacerbate corrosion.

A voltammetric procedure is described which allows determination of rate constants for reactions of hydroxyl radicals. Hydroxyl radicals, generated by reaction of an iron-EDTA complex with H 2 O 2 in the presence of ascorbic acid, attack deoxyribose to form products that, upon heating with thiobarbituric acid under acid conditions, yield a pink chromogen with second order derivative cathodic wave at −0.88 V vs SCE. Added hydroxyl radical `scavengers' compete with deoxyribose for the hydroxyl radicals produced and diminish chromogen formation. The electrochemical behavior of the chromogen has been determined using voltammetry and cyclic voltammetric techniques. A rate constant for reaction of the scavenger with hydroxyl radical can be deduced from the inhibition of chromogen formation. For a wide range of compounds, the results fit well with rate constants previously obtained with other methods. It is suggested that voltammetric deoxyribose assay is a simple and cheap alternative for determination of rate constants for reaction of most biological molecules with hydroxyl radicals. Rate constants for reactions of six kinds of active compounds extracted from rheum, a traditional Chinese herb, have been determined by this method. Reaction mechanism has also been discussed.

Galvanic corrosion of a 6092-T6 Al metal-matrix composite (MMC) reinforced with boron carbide (B 4 C) particulates was examined through electrochemical characterization of the MMC as well as a monolithic B 4 C. The results were interpreted based on a recently proposed electronic model for B 4 C that emphasizes a conventional non-degenerate p-type semiconductor band structure with high density of gap states. The electrochemical behavior of B 4 C in the dark that was characteristic of non-active metal electrodes was attributed to the very high density of gap states of B 4 C; while the phenomenon of the enhanced cathodic currents of B 4 C under illumination was attributed to the presence of a depletion layer at the B 4 C/electrolyte interface, characteristic of non-degenerate p-type semiconductor/electrolyte interface. The results suggested that galvanic corrosion of the MMC in the dark was limited by slow oxygen reduction kinetics at the B 4 C reinforcements and that illumination promotes galvanic corrosion of the MMC as a result of photo-enhanced cathodic activity of the B 4 C reinforcements. Scanning electron microscopy revealed that corrosion of the MMC initiated from carbon particles that are likely introduced into the matrix during the processing of the MMC. A combination of scanning vibration electrode technique and scanning ion-selective electrode technique revealed that localized anodic and cathodic sites co-exist during the corrosion of the MMC in an air-exposed 3.15 wt % NaCl solution. The localized anodic and cathodic sites have diameters of approximately 200 μm.

The microstructure and corrosion initiation sites of particulate alumina reinforced 6092 T6 Al metal-matrix composites (MMCs) (1, 2) were examined with scanning electron microscopy (SEM) and energy dispersive X-ray Analyzer (EDXA). The MMC contained a variety of Ticontaining micro-particles (Figure 1) that were very likely introduced into the Al matrix as impurities of the alumina reinforcements. The reduction product of CuSO4 precipitated onto the Ti-containing particles, suggesting that the Ti-containing particles conducted cathodic reactions. When the MMC was immersed in salt water in open-circuit conditions, micro-crevices formed around both the Ti-containing particles as well as Fe-Si-Al intermetallic particles. With the semi-quantitative EDXA technique, the Ti-containing particles that induced microcrevices can be roughly divided into three categories: 1) titanium suboxides with compositions close to that of Ti6O, Ti3O, Ti2O and TiO; 2) Ti-Zr-Al oxides; and 3) TiO2. Although little is known about the electrical properties of the titanium suboxides and the Ti-Zr-Al oxides, the results suggested that these compounds were either electrically conducting or semi-conducting. As for the TiO2 particles (3), it was hypothesized that 1) the TiO2 particles were reduced and consequently n-doped by the processing of the MMC (e.g., hot-pressing and T6 heat treatments); and 2) the flatband potential of the TiO2/electrolyte system might be close to the open-circuit potentials of the MMC in air-exposed salt water, making cathodic reactions at the TiO2 surfaces feasible. Microcrevices also formed around some particles with an oval structure (Figure 2). The core region of the oval structure appeared to be a Ti-Si-Al phase while the shell region of the oval structure appeared to be an Fe-Si-Al phase.

A modified photochemical-diode (PD) model, designated as a photochemical-corrosion-diode (PCD) model, was proposed for interpreting galvanic corrosion in metal-matrix composites (MMCs) containing semiconducting constituents. The characteristics of the PCD model were introduced through direct comparison with that of the PD model. The PCD model was then used to interpret galvanic corrosion in SiC-reinforced Al MMCs. The PCD model and the photoelectrochemical experiments on both Al/SiC MMCs and monolithic SiC predicted that solar irradiation may affect the corrosion of the Al/SiC MMCs, corroborating well with field experiments.

The corrosion rates of particulate 6092-T6 Al metal-matrix composites (MMCs) reinforced with 20 vol % B 4 C, SiC, and Al 2 O 3 as well as monolithic 6061-T6 Al immersed in American Society for Testing and Materials (ASTM) and real seawaters were lower than those immersed in 3.15 wt % NaCl or 0.5 M Na 2 SO 4 solutions. Scanning electron microscopy revealed that precipitates consisting of agglomerated whiskers formed on the surfaces of the MMCs and the monolithic 6061-T6 Al after prolonged immersion in seawater environments. The precipitates were tentatively identified to be Al-Mg hydrotalcite-like compounds based on energy-dispersive X-ray analyses and X-ray diffraction experiments. The MMCs immersed in ASTM seawater exhibited localized corrosion, however, the scanning ion-selective electrode technique revealed smaller pH fluctuations near the localized corrosion regions compared to the MMCs immersed in NaCl and Na 2 SO 4 solutions. It was postulated that the corrosion of the Al-based materials is inhibited both by the precipitates and by the buffering effect of seawater.

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Galvanic corrosion of an Al-based metal-matrix composite (MMC) reinforced with 40 wt % Si particulates was examined by considering the semiconductor/electrolyte junction properties of the Si reinforcements. Scanning capacitance microscopy and photoelectrochemical experiments indicated that the Si reinforcements were slightly p-doped. At the open-circuit condition, a wide depletion layer was expected to be present at the slightly p-doped Si surface. The blocking characteristics of the depletion layer for electrochemical reactions would thus limit the galvanic interactions between the Si reinforcements and the Al matrix. The photoelectrochemical experiments also suggested that solar irradiation may promote galvanic corrosion because of the enhanced cathodic activity of the Si reinforcements under illuminated conditions. Corrosion was found to initiate from Fe-containing intermetallics, which served as effective cathodes. A chemical decoration method indicated that, while the bulk region of the Si reinforcements was not effective for cathodic reactions, the exposed Si surfaces at the Al/Si interfaces were effective cathodic sites. It was hypothesized that (i) during the processing of the Al/Si MMC, interdiffusion caused the Si surfaces at the Al/Si interfaces to be highly p-doped with Al, and (ii) upon propagation of localized corrosion from the sites adjacent to the Fe-containing intermetallics, the highly p-doped Si surfaces were exposed to solution and served as effective cathodic sites to induce galvanic corrosion. A scanning vibrating electrode technique revealed a net cathodic current over the localized corrosion regions, which were many times larger than the intermetallic particle or the Si reinforcement particle. Accordingly, the solution near the localized corrosion regions was alkalinized, as was revealed by the scanning ion-selective electrode technique.

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Particulate 6092-T6 Al metal matrix composites (MMCs) reinforced with of , SiC, and exhibited localized corrosion when immersed in a solution exposed to air at room temperature. For the MMCs reinforced with and SiC, the scanning vibrating electrode technique (SVET) revealed that corrosion initiated at localized anodic regions, which transformed into cathodic regions over time. The scanning ion-selective electrode technique (SIET) revealed that the localized anodic regions were acidified, and the localized cathodic regions were alkalinized. The observed anodic-cathodic transformation behavior was attributed to aluminum which has amphoteric oxides, the formation of microcrevices by reinforcement particles left in relief, and the possible galvanic action between the 6092-T6 Al matrix and the and SiC reinforcement particles. The localized anodic and cathodic regions were many times larger than the individual reinforcement particle size. For the -reinforced MMC, localized corrosion coincided with regions showing some cathodic activity and alkalinity. The extent of corrosion of these three MMCs was found to increase with decreasing reinforcement resistivities ρ (i.e., ).

Electrochemical polymerization of aniline onto a gold electrode surface in an aqueous electrolyte solution containing a small amount of polyelectrolyte, i.e., sodium poly(styrenesulfonate) (Na-PSS), and the characterization of the resulting polyaniline (PAn)/poly(styrenesulfonate) (PSS) composite have been studied using electrochemical quartz crystal microhalance and other electrochemical experiments. The entrapment of the polyelectrolyte affected the electrochemical properties, morphology, and structure of the polymer film as evidenced by the results of cyclic voltammetry and scanning electron microscopy experiments hut did not affect the growth rate, as the increases in charge measured during the polymerization process are identical regardless of whether the polyelectrolyte is present or not. Surprisingly, the PAn/PSS composite thus formed had dominantly anion-exchanging characteristics, which is not in agreement with what has been generally believed for this type of composite polymer. The ion-exchanging properties were found to be pH dependent.