Structural regulation of vanadium oxide by poly(3,4-ethylenedioxithiophene)intercalation for ammonium-ion supercapacitors

Recently,ammonium-ion(NH_(4)^(+))storage is in a booming stage in aqueous energy storage systems due to its multitudinous merits.To seek suitable electrode materials with excellent NH_(4)^(+)-storage is still in the exploratory stage and full of challenge.Herein,an inorganic-polymer hybrid,poly(3,4-ethylenedioxithiophene)(PEDOT)intercalated hydrated vanadium oxide(VOH),named as VOH/PEDOT,is developed to tune the structure of VOH for boosting NH_(4)^(+)storage.By the intercalation of PEDOT,the interlayer space of VOH is increased from 11.5Åto 14.2Å,which notably facilitates the rapid transport of electrons and charges between layers and improves the electrochemical properties for NH_(4)^(+)storage.The achieved performances are much better than progressive NH_(4)^(+)hosting materials.In addition,the concentration of polyvinyl alcohol/ammonium chloride(PVA/NH_(4)Cl)electrolyte exerts a great impact on the NH_(4)^(+)storage in VOH/PEDOT.The VOH/PEDOT electrode delivers specific capacitance of 327 F g^(-1)in 1 M PVA/NH_(4)Cl electrolyte at-0.2–1 V.Furthermore,the quasi-solid-state VOH/PEDOT//active carbon hybrid supercapacitor(QSS VOH/PEDOT//AC HSC)device is assembled for NH_(4)^(+)storage,and it exhibits the capacitance of 328 mF cm^(-2)at 1 mA cm^(-2).The energy density of QSS VOH/PEDOT//AC NH4 t-HSC can reach 2.9 Wh m^(-2)(2.6 mWh cm^(-3),10.4 Wh kg^(-1))at 1 Wm^(-2)(0.9 mWh cm-3,35.7 W kg^(-1)).This work not only proves that the PEDOT intercalation can boost the NH_(4)^(+)storage capacity of vanadium oxides,but also provides a novel direction for the development of NH_(4)^(+)storage materials.

Dielectric Investigations on How Mg Salt Is Dispersed in and Released from Polylactic Acid

Composite biomaterials made of biodegradable polylactic acid （PLA） and bioactive magnesium （Mg） salt are developed for orthopaedic implants or metal implant coatings. The releasing of Mg salt into the biological environment benefits the bone growth, while with the releasing of Mg salt and degradation of PLA there forms a porous scaffold for tissue engineering. The size and morphology of the salt and voids are adjustable with such preparation conditions as salt content, pH of casting solution, and the solidification rate, so that we can control the salt releasing and degradation rate of PLA. Dielectric spectroscopy is used to investigate the dispersive structures of Mg salt and voids in the polymer matrix and to monitor the in situ releasing of Mg salts in the simulated body fluid （SBF）. The current study provides us with an orthopedic biomaterial with controllable multi-phase structures, and a tool to investigate the in vivo behaviors of biomaterials.