TEMPO-substituted polyacrylamide for an aqueous electrolyte-typed and organic-based rechargeable device

A hydrophilic radical polymer, poly(2,2,6,6-teteramethylpiperidinyloxyl-4-yl acrylamide) (PTAm), was synthesized via oxidation of the corresponding precursor polymer, poly(2,2,6,6-teteramethylpiperidine-4-yl acrylamide). Electrochemical properties of the PTAm layer were characterized in three aqueous electrolytes of sodium chloride (NaCl), sodium tetrafluoroborate (NaBF4), and sodium hexafluorophosphate (NaPF6) to optimize its activity as an organic cathode. The counter anion species significantly affected the capacity and the cycle performance of the PTAm layer. The PTAm layer in the presence of BF4? displayed quantitative redox capacity beyond 1 μm layer thickness and maintained the discharging capacity of 110 mAh g-1 (97% vs. the calculated capacity) even after 1000 cycle charging/discharging, which could be ascribed to its appropriate affinity to the aqueous electrolyte without any dissolution into the electrolyte. A totally organic-based rechargeable cell was fabricated using PTAm and poly(N-4,4’-bipyridinium-N-decamethylene dibromide) as the cathode and the anode, respectively, and the aqueous electrolyte of NaBF4. The cell gave a plateau voltage at 1.2 V both on charging and discharging and an excellent charging/discharging cyclability of >2000 with high coulombic efficiency of >95%.     

Insight into the development of electrolytes for aqueous zinc metal batteries from alkaline to neutral

Aqueous zinc metal batteries are considered as promising candidates for next-generation electrochemical energy storage devices, especially for large-scale energy storage, due to the advantages of high-safety,high energy density and low cost. As the bridge connecting cathode and anode, electrolyte provides a realistic operating environment. In alkaline and neutral aqueous zinc metal batteries, issues associated with electrolyte and anode are still intractable. In this review, we reveal the develo...     

A symmetric aqueous redox flow battery based on viologen derivative

Due to the diversity and feasibility of structural modification for organic molecules,organic-based redox flow batteries(ORFBs) have been widely investigated,especially in aqueous solution under neutral circumstance.In this work,a symmetric aqueous redox flow battery(SARFB) was rationally designed by employing a bipolar redox active molecule(N,N'-dimethyl-4,4-bipyridinium diiodide,MVI_2) as both cathode and anode materials and combining with an anion exchange membrane.For one MVI_2 flow battery,MV~(2+)/MV~(·+) and I~-/I_3~-serve as the redox couples of anode and cathode,respectively.The MVI_2 battery with a working voltage of 1.02 V exhibited a high voltage efficiency of 90.30% and energy efficiency of 89.44% after 450 cycles,and crossover problem was prohibited.The comparable conductivity of MVI_2 water solution enabled to construct a battery even without using supporting electrolyte.Besides,the bipolar character of MVI_2 battery with/without supporting electrolyte was investigated in the voltage range between-1.2 V and 1.2 V,showing excellent stable cycling stability during the polarity-reversal test.     

Study on photoconductivity of dye-polymer-based solid-state thin film

In this article, we describe a solid-state photoelectrochemical cell for light detection. Safranine-T dye mixed with polyvinyl alcohol (PVA) solution was deposited on a conducting and transparent indium-tin-oxide (ITO)-coated glass that was used as one electrode and another ITO-coated glass as the counterelectrode. A solid polymeric electrolyte consisting of polyethylene oxide-ammonium perchlorate-ethylene carbonate and propylene carbonate with suitable weight ratio was prepared and sandwiched between these two ITO-coated glass electrodes, which were separated by a Teflon spacer about 50 μm thick. The cell was biased with a direct current source to make the dye and PVA-coated ITO as the anode and the other ITO as the cathode. On illumination by a tungsten lamp, from the cathode side, the change of photocurrent was measured. The dark current-voltage characteristics and the growth and decay of the photocurrent for steady and pulsed illumination were studied.     

Effects of Various Dopants on Solitons in Polyacetylene

The effects of various dopants on solitons in polyacetylene were studied by using CNDO/2 level semiempirical quantum chemical method. The width of solitons is reduced when dopant is present, and the charge density wave(CDW) is further gathered on the carbon atom in soliton center. The effects of p-type of dopants are greater than those of n-type of ones. The charge transfer in doped polyacetylene can be achieved by the propagation of CDW along the chain. The conductivity of doped polyacetylene is proportional to the quantity of charge transfer between dopant and polyacetylene chain.     

氧化铝对稀土有机配合物掺杂溶胶凝胶玻璃结构及发光性能的影响

Both silica glass materials singly doped with rare earth organic complex and co-doped with Al^3 were prepared by in situ sol-gel method respectively. XRD and SEM measurements were performed to verify the non-crystalline structure of the glass. The excitation spectra, emission spectra and IR spectra were measured to analyze the influence of the glass contents on the structure of the glass and the energy level of the doped Eu(IH) ions. The effect of Al^3 on the photoluminescence properties of rare earth organic complex in silica glass was investigated. The IR spectra indicated that the in situ synthesized europium complex molecule was confined to the micropores of the host and the vibration of the ligands was frozen. When Al2O3 was doped into the silica host gel, the rare earth ions in the silica network were wrapped up and dispersed by Al2O3, so the distribution of Eu(Ⅲ) complex in the host was morehomogeneous, and the luminescence intensity of ^5D0-^7F2 transition emission of the Eu^3 ions was improved. The results showed that an appropriate amount of Al^3 added to the gel glass improved the emission intensity of the complex in the silica glass, and when the content of Al2O3 reached 4 mol%, the maximum emission intensity could be obtained compared with that of other samples containing different Al2O3 contents.     

Stabilizing the Electrochemistry of Lithium-Selenium Battery via In situ Gelated Polymer Electrolyte: A Look from Anode

Li metal possesses a high theoretical specific capacity,high electronic conductivity,and a low electrochemical potential,making it a promising anode material for building next-generation rechargeable metal batteries.In case conventional liquid electrolytes were used,and the anode using Li metal has been hindered by unstable(electro)chemistry at Li/electrolyte interface and the accompanied dendrite issue.Specifically,for the Li-Se batteries,the dissolution and shuttle of polyselenide intermediates lead to the deposition of poorly-conductive species on the anode,which further aggravates the chemical environment at the anode.In this work,we proposed to stabilize the Li-Se electrochemistry by constructing a gel polymer electrolyte via in situ gelations of conventional ether-based electrolytes at room temperature.The results demonstrate that the in situ gelated electrolyte helps to build electrochemically stable electrode/electrolyte interfaces and promote the efficient transfer of charge carriers across the interface.Compared with the liquid electrolytes,the gelated electrolyte shows improved chemical compatibility with the Li metal anode,which effectively alleviates the unfavorable side reactions and dendrite formation at the anode/electrolyte interface,and the polyselenide shuttle from the cathode to the anode.As a result,the Li-Se battery shows a higher Coulombic efficiency and improved cycling performance.     

Ca、Ce双掺杂烧绿石型复合氧化物的合成及离子导电性能研究

Pyrochlore-type rare earth complex oxides of La_2-αCa_αZr_2-βCe_βO_7-δ were synthesized by the sol-gel method. The structure of the samples was characterized by X-ray diffraction (XRD). The ionic conduction in solid electrolyte of the sintered samples was examined using electrochemical methods at 400～800 ℃. The result indicated that the samples were pyrochlore-type structure, conductivities of the Ca and Ce doped samples were largely increased. Ammonia was synthesized from nitrogen and hydrogen at atmospheric pressure in the solid state proton conducting cell reactor. The ammonia evolution rate of doped samples is larger than that of the undoped ones, which indicates that the samples are proton conductor and the ability of protonic conductivity is mainly decided by hole concentration.     

Precise in-situ and ex-situ study on thermal behavior of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2/graphite coin cell:From part to the whole cell

Multiple mode calorimetry and C80 micro-calorimeter are used to investigate the impact of cathode and anode on heat generation of lithium ion battery.The thermal behaviors of LiNi_xCo_yMn_zO₂/graphite full cell are discussed under normal operating and elevating temperature.Affected by negative entropy change,lithium intercalation presents more exotherms than deintercalation for both electrode materials.The contributions of irreversible and reversible heat to the total heat generation of graphite are evaluated.The phase transitions correlated with voltages and lithium contents are determined.Based on the analysis of half-cell,the effect of two electrodes(with the same capacity)on overall heat generation is nearly the same and anode of full cell plays a key role in charging while cathode dominates in discharging.Thermal behaviors of lithiated graphite and delithiated LiNi_xCo_yMn_zO₂ electrolyte and their coexisting system are identified to further explore their influence on battery safety.The breakdown of solid electrolyte interface(SEI)at around 82℃ is considered as a crucial factor affecting the thermal stability of full cell.The oxidation of electrolyte induced by oxygen released from cathode material turns out to be one of the main heat sources.These accurate results are of great significance to improve the existing thermal management system and provide basic data for the prediction of battery performance.     

Luminescence properties of sol-gel derived silica gels doped and undoped with RE-complexes(RE=Eu,Tb)

The luminescence properties of silica gels and silica gels doped with two rare earth complexes,Eu(TTA)3 and Tb(o-CBA)3 (TTA=thenoyltrifluocetate,o-CBA=o-chlorobenzoic acid) are reported and discussed.Pure silica gels show a blue luminescence,and the maximum excitation and emission wavelengths depend strongly on the solvents used.Both of the studied rare earth complexes exhibit the characteristic emissions of the rare earth ions in silica gels,i.e.,Eu3+5 Do→7 FJ(J=0,1,2,3,4),Tb3+5D4→7FJ(J=3,4,5,6) transitions.Compared with the pure RE-complexes powder,the silica gels doped with RE-complexes show fewer emission lines of the rare earth ions.Furthermore the rare earth ion (Tb3+) presents a longer lifetime (1346μs) in silica gel doped with Tb(o-CBA)3 than in pure Tb(o-CBA)3 powder (744μs).The reasons responsible for these results are discussed in the context.