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This study presents the synthesis and characterization of a novel glucose electrochemical biosensor based on gold nanoparticles/bovine serum albumin/Fe 3 O 4 (AuNPs/BSA/Fe 3 O 4 ) composite nanoparticles. The prepared magnetic composite nanoparticles consist of a BSA protein shell, providing biocompatible environment for enzyme immobilization. Furthermore, in situ immobilization of gold nanoparticles greatly enhances the performance of electron transfer. Using these composite nanoparticles, the model enzyme, glucose oxidase (GOx) was readily adsorbed to surface so as the GOx/AuNPs/BSA/Fe 3 O 4 electrochemical biosensor was developed. The electrochemical performance of the biosensor was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry. Under the optimal preparation conditions, the resultant biosensor has a short response time of 0.8 s, an excellent sensitivity of 115.3 μA mM −1 cm −2 , and a linear dynamic range from 0.25 to 7.0 mM with a low detection limit of 3.54 μM (S/N = 3). The high sensitivity, good reproducibility and stability of the biosensor presented in this study show that the as-prepared AuNPs/BSA/Fe 3 O 4 composite nanoparticles are a promising material for the development and construction of biosensors. [ABSTRACT FROM AUTHOR]

Abstracts Silicon (Si) is regarded as one of the most promising anode materials for Li-ion batteries due to its high theoretical specific capacity (4200 mAh g −1 ). To overcome the poor cycling stability issue associated with its low conductivity and large volume changes (∼300%) during charge/discharge processes, a novel approach to fabricate three-dimensional (3D) network structure of silicon-graphene-polyaniline (Si-G-PANI) has been developed. During this synthetic, the graphene sheet was first coated on the surface of Si from a pyrolysis reaction of the liquid-polyacrylonitrile (LPAN), which not only improves conductivity but also constrains the serious mechanical stress caused by the volume expansion of Si. Subsequently, Si-G-PANI composite was obtained through an in-situ polymerization, the PANI layer is tightly bounded to graphene owing to an enhancement of π conjugation between the PANI and graphene-grafted Si nanoparticles. Herein, PANI layer offers a 3D conductive and protective network to allow the volume variation of Si during cycling, as well as facilitate the electron and lithium ion transfer processes. With the dual protection of graphene and PANI, the Si-G-PANI electrode can deliver a reversible specific capacity of 1001.8 mAh·g −1 at a current density of 1.5 A g −1 after 50 cycles. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting by electricity from the renewable power sources is one of the most promising pathways for green and sustainable hydrogen production. The key is to synthesize earth-abundant and noble-metal-free electrocatalysts with outstanding hydrogen evolution reaction (HER) activity and durability in wide-pH electrolytes by simple and cost-effective methods. Herein, we reported a one-step synthesis of uniform, ultrafine molybdenum carbide (Mo 2 C) and molybdenum nitride (Mo 2 N) hybrid [together as Mo 2 (CN)] inserted carbon nanosheets as efficient electrocatalyst for HER. The as-synthesized catalyst showed an excellent HER activity in acid medium, and even superior performance was obtained in the alkaline medium. The optimal Mo 2 (CN) annealed at 750 °C showed an overpotential of −80 mV at 10 mA cm −2 and a Tafel slope of 40 mV dec −1 ; the former strikingly outperforms commercial 20% Pt/C materials (−112 mV). Moreover, Mo 2 (CN) gave an onset voltage of −33 mV and overpotential of −202 mV at 100 mA cm −2 with merely a mass loading of 0.2 mg cm −2 , which are, to date, among the best records for Mo-based catalysts in both media. The nanosheet structure providing large active area and quick charge transfer, and the synergistic effects between Mo 2 C and Mo 2 N toward HER are ascribed to the outstanding electrocatalytic activity according to the capacitive current and turnover frequency analysis. The remarkable catalytic activity and operational durability in wide pH ranges guarantee their potential for highly efficient hydrogen production. [ABSTRACT FROM AUTHOR]

The ability to develop low-cost highly efficient electrocatalyst for oxygen evolution reaction (OER) is key to the overall water splitting device that represents a viable and promising source of alternative energy. Herein, we crafted three-dimensional (3D) network comprising nitrogen-doped graphitic carbon-coated heterojunctions (denoted NC-Ni 0.36 Fe 0.64 /MnO x ) via one-step calcination of hybrid precursors containing ternary Prussian blue analogues and polymers. The NC-Ni 0.36 Fe 0.64 /MnO x nanocomposites were then exploited as catalysts for OER, displaying exceptional performance with a small overpotential of 300 mV to reach 10 mA cm −2 , a low Tafel slope of 43 mV/dec and an outstanding stability without deactivation over a 10-h OER. Notably, compared to commercial RuO 2 catalysts, NC Ni 0.36 Fe 0.64 /MnO x catalysts demonstrated much lower overpotential and Tafel slope. The excellent OER performance can be attributed to the presence of high-valence oxidized metal species (Ni 2+ , Fe 2+ and Mn 2+ ) at the heterostructured interface as well as pyridinic N-doped carbon species on highly conductive graphitic carbon network, thus greatly facilitating the electron-withdrawing from OH − and thus charge transfer during OER. This simple yet effective strategy may open new possibilities for creating a wide range of low-cost, high-efficiency, non-precious transition metal OER catalysts for the overall water splitting. [ABSTRACT FROM AUTHOR]

Li 4 Ti 5 O 12 particles are synthesized coated with very thin graphene-like sheets in situ using liquid-polyacrylonitrile (LPAN) as the carbon source and added utilized conductivity additives to improve the conductivity of the electrode materials. The crystalline structures of Li 4 Ti 5 O 12 with 20% LPAN and different conductivity additives composites were examined by XRD. The structure and electrochemical performance of the graphene-like sheets coated Li 4 Ti 5 O 12 , with conductivity additives added, was systematically investigated. The electrochemical performance also revealed that the graphene-like sheets significantly improved the discharge capacity and cycling stability of Li 4 Ti 5 O 12 . In particular, the coated Li 4 Ti 5 O 12 with 20 wt% LPAN and 1% acetylene black (CB) reached 166.2 mAh g −1 at 10C. The performance improvement is a result of the graphene-like nanosheet conformal coating, which creates an electrically conductive network for the electrode. [ABSTRACT FROM AUTHOR]

The vanadium oxides with classical high-capacity materials as well as high operating voltage have been regarded as appealing electrodes for aqueous zinc-ion batteries (AZIBs) owing to their multiple valences and adjustable ion-diffusion channels. However, the developed AZIBs cathodes have always suffered from sluggish Zn2+ diffusion kinetics and less stable layered structure, thus resulting in the inadequate electrochemical performance. In this work, unique organometallic (ferrocene) reintercalated inorganic (vanadium oxide) cathodes (Fec/O d -VO) with defective crystal structure were firstly synthesized via a redox intercalation method for ultrahigh-rate and ultralong-life aqueous ZIBs. The unique organometallic can not only enlarge interlayer distances between the V-O layers, with expediting channels for fast Zn2+ diffusion, but also introduce the rich oxygen vacancies to facilitate the surface reversible Zn2+ adsorption. The resulting Fec/O d -VO displays a high discharge capacity (411.7 mAh g−1 at 0.5 A g−1) and superior long-term cycling stability (86.5% retention over 3000 cycles at 20 A g−1). This enlightened design combining interlayer regulation with oxygen defect engineering proves to be a new modus operand toward advanced AZIBs by redox intercalation of unique organometallic. [ABSTRACT FROM AUTHOR]

Non-noble-metal catalysts have shown promising oxygen reduction reaction (ORR) activity in proton exchange membrane fuel cells (PEMFCs). Herein, by using sulfur-terminated fluidic acrylonitrile telomere (ANT) as precursor, an N and S dual-doped Co/ANT/C catalyst was prepared via a facile heat treatment of the mixture of Co salt, ANT and carbon black, in which cobalt salt was uniformly-dispersed and interacted with ANT. As such, the increasing contact area between ANT and cobalt salt leads to a highly catalytic activity toward oxygen reduction reaction. Most importantly, by using ANT as precursor, the catalyst showed a remarkable improvement in the onset potential and current density as compared with those prepared from pure carbon black, cobalt salt/C or catalyst using high molecular weight polyacrylonitrile as precursor. Besides, the as-made Co/ANT/C catalyst demonstrated a comparable catalytic activity with commercial expensive Pt/C at high loading. In addition, the catalyst participated promotes a direct four-electron reduction of O 2 to H 2 O and long term operation stability in an alkaline medium. Owing to its superb ORR performance, low cost and facile synthesis approach, such prepared Co/ANT/C catalyst has great potential applications in PEMFCs. [ABSTRACT FROM AUTHOR]

• PEO-based polymer electrolyte with KPF 6 additive was developed for improving the performance. • KPF 6 can reduce the crystallinity of PEO, and promote dissociations of LiTFSI. • KPF 6 can increase the ionic conductivity of PEO-based polymer electrolyte. • KPF 6 salt can regulate the formations of Li 2 S/LiF-rich SEI layer. • Li 2 S/LiF-rich SEI layer and K + electrostatic shielding led to a uniform Li deposition. High energy density all-solid-state lithium metal batteries (ASSLMBs) with flexible, low-cost solid polymer electrolytes (SPEs) have received extensive research attention, but the low ionic conductivity of SPEs and the rapid growth of lithium dendrite seriously limit their performance. Here, polyethylene oxide (PEO) based solid polymer electrolytes (SPEs) containing potassium hexafluorophosphate (KPF 6) salt additive are developed for lithium dendrite-free ASSLMBs. The results show that with the additive of KPF 6 , the dissociation of lithium salt is promoted, providing more free Li+ ions in SPEs and enhancing the ionic conductivity. KPF 6 additive also makes SPE more flexible and promotes the formation of Li 2 S and LiF-rich solid electrolyte interphase (SEI). Besides, the presence of K + is also expected to work as a shield to inhibit the lithium dendrite growth. With the synergistic effect of above advantages, lithium dendrite growth and interfacial side-reactions in ASSLMBs are prevented. Li/Li symmetric cell with SPE can achieve a stable cycling performance over 1500 h with low polarization potential. The all-solid-state LiFePO 4 /Li cell releases an initial capacity of 142.1 mAh g−1 with a capacity retention of 91.3% after 200 cycles at 0.5 C and 60 °C. This study provides a facile scheme for designing high performance ASSLMBs. [Display omitted] Solid-state lithium metal batteries with polyethylene oxide (PEO) based solid polymer electrolytes (SPEs) suffer from lithium dendrite problems. To address this challenge, KPF 6 is used as an additive to improve ionic conductivities and mechanical properties of SPEs. Moreover, KPF 6 is favorable to the formation of LiF-rich solid electrolyte interphase. K + also works to suppress the lithium dendrite through shielding effects. [ABSTRACT FROM AUTHOR]

This paper reveals a novel Li-rich layered cathode material Li[Li 0.1 Ni 0.45 Mn 0.45 ]O 2 in situ coated with graphene-like carbon prepared by using liquid-polyacrylonitrile (LPAN) as the carbon source. The structure and electrochemical performance of graphene-like carbon coated Li[Li 0.1 Ni 0.45 Mn 0.45 ]O 2 are investigated systematically. The results demonstrate that the graphene-like carbon are in situ coated tightly on the surface of Li[Li 0.1 Ni 0.45 Mn 0.45 ]O 2 particles. The in-situ coating of graphene-like carbon significantly improves the electrochemical properties of cathode materials. The discharge capacity of cell made of 12wt% LPAN-coated Li[Li 0.1 Ni 0.45 Mn 0.45 ]O 2 can reach 210 mAh g −1 and the capacity retention is close to 100% after 50 cycles at 0.1C. The cyclic voltammgram and electrochemical impedance spectra analyses further demonstrate that the improved electrochemical performance of LPAN-coated Li[Li 0.1 Ni 0.45 Mn 0.45 ]O 2 cathode materials is attributed to the graphene-like carbon in situ coating, which can protect the cathode directly contact with the electrolyte. Therefore, the Li-rich layered Li[Li 0.1 Ni 0.45 Mn 0.45 ]O 2 in situ coated with graphene-like carbon is a very good promise cathode material for advanced LIB with high capacity and good stability. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO 2 under the high temperature electrolysis condition with favored kinetics is a promising method to utilize and convert CO 2 to valuable chemicals and to reduce its environmental impact. In this work, the electrochemical performance of perovskite-type La 0·3 Sr 0·7 Fe 0·7 Ti 0·3 O 3 (LSFT) oxide was thoroughly investigated as a cathode for high temperature solid oxide electrochemical reduction under practical CO 2 electrolysis conditions of various current densities, partial pressures, and different CO–CO 2 mixtures. The rate-limiting step of CO 2 reduction on the LSFT surface was determined by the electrochemical impedance spectroscopy technique with a three-electrode configuration. The exceptional performance of LSFT cathode is confirmed as reflected by the low polarization resistance and the extremely low activation energy. Moreover, improved electrode performance is also obtained on the reduced LSFT sample under reducing atmosphere with CO, while the rate-determining step is not changed. It is also confirmed that the reduced LSFT cathode gives increased surface oxygen vacancy concentration which is believed to serve as accommodation for chemical adsorption and consequently the active sites for electrochemical activation of CO 2 , leading to the improved electrochemical performance. • Electrochemical activity under practical CO 2 reduction condition is studied. • Cathode polarization of LSFT for CO 2 reduction is verified with 3-electrode study. • LSFT shows super-low polarization and activation energy for CO 2 reduction in SOEC. • Reduced LSFT with increased oxygen vacancies benefits the HT chemical adsorption and activation. [ABSTRACT FROM AUTHOR]