Novel carbon-based microporous nanoplates containing numerous heteroatoms (H-CMNs) are fabricated from regenerated silk fibroin by the carbonization and activation of KOH. The H-CMNs exhibit superior electrochemical performance, displaying a specific capacitance of 264 F/g in aqueous electrolytes, a specific energy of 133 Wh/kg, a specific power of 217 kW/kg, and a stable cycle life over 10000 cycles.

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The influence of Bi modification of Pt anode catalyst on the performance of direct formic acid fuel cells was investigated. Compared with the unmodified Pt anode, the Bi modified Pt (PtBi(m)) electrode prepared by under-potential deposition (UPD) caused faster electrocatalytic oxidation of formic acid at the same value of the overpotential, and thus, PtBi(m) resulted in an increase in the power performance of direct formic acid fuel cells. Electrochemical impedance spectra helped to explain the difference of performance between the unmodified Pt and Bi modified Pt electrodes. Solution conductivity and dehydration phenomena occurring in highly concentrated formic acid solutions can also explain the higher power performance of PtBi(m).

An aluminum metal, both native and with a very thin oxide film, was investigated as an anode for aluminum-ion batteries. Investigations were carried out in an acidic ionic liquid electrolyte, composed of AlCl in 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl), with β-MnO/C as a cathode. The battery based on Al metal with a very thin oxide film showed high capacity and stable surface corrosion.

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Lithium phosphorous oxynitride ͑Lipon͒ films were deposited in N 2 gas atmosphere with different radio-frequency magnetron sputtering power from 80 to 160 W with 20 W step increase. Lipon films deposited at lower sputtering power showed higher ionic conductivities than the films deposited at higher sputtering power. The results of impedance measurements showed that nitrogen incorporation into the glass structure increased the ionic conductivity and this nitrogen content in the Lipon films increased as the sputtering power decreased. In addition, the Auger electron spectroscopy depth profile showed that the increased nitrogen content in the Lipon films was not the result of the target surface poisoning effect but the result of reactive incorporation of nitrogen. The miniaturization of electronic devices has resulted in very low current and power requirements for many applications ͓comple-mentary metal oxide semiconductor ͑CMOS͒ CMOS back up, smart cards, implantable medical devices, microelectromechanical system ͑MEMS͔͒. Microenergy sources must be developed to drive these small electronic devices. A thin film battery ͑TFB͒ is one of the options for satisfying this demand. To make the thin film battery, a thin film solid electrolyte is indispensable.Solid electrolytes have several advantages over liquid electrolytes, such as no leakage problem, broad operating temperature range, excellent charge-discharge cyclic properties due to a lack of side reactions occurring and only one type of carrier ion migration, and long life because of little self-discharge. Such solid electrolytes should have properties such as a very high ionic conductivity, negligible electronic conductivity, and a very low activation energy.Ion conducting glasses are generally composed of three components, a network former, a network modifier, and a doping salt. The absence of structural constraints allows easy modification of their relative contents to optimize electrical and electrochemical properties. They are usually made by conventional melt-quenching.Based on this theory, several solid electrolytes were studied such as Li 2 S-P 2 S 5 -LiI, 17 Among these, Li 2 S-based solid electrolytes are unstable in contact with Li metal used as an anode and also unstable in atmosphere, although they show high ionic conductivities. On the other hand, while Li 2 O-based solid electrolytes are easy to handle in atmosphere, they show low ionic conductivities and the stability problem with Li metal contact is not solved.Recently, a new Li ϩ ion conducting solid electrolyte lithium phosphorous oxynitride ͑Lipon͒ was developed and has been successfully incorporated into rechargeable thin-film lithium batteries by Oak Ridge National Lab. 18,19 This material is stable with Li metal, easy to handle in atmosphere and shows high ionic conductivity. This amorphous material is deposited by sputtering Li 3 PO 4 in N 2 gas, and its composition can be represented by xLi 2 O:yP 2 O 5 :zPON, where PON is phosphorus oxynitride. Lipon films prepared in this way show high io...

Aluminum-ion batteries are considered to be a promising post lithium-ion battery system in energy storage devices because aluminum is earth-abundant, has a high theoretical capacity, and is of low cost. We report on the chemical activities and stabilities of chloroaluminate anions [Al Cl] with aluminum metal using a different mole ratio of AlCl and 1-ethyl-3-methylimidazolium chloride. The morphological changes in the Al metal surface are investigated as a function of dipping time in electrolyte, revealing that the Al metal surface is locally attacked by chloroaluminate anions followed by the formation of a new Al oxide layer with a specific lattice plane and a craterlike surface around the cracking site. The aluminum-ion battery exhibits outstanding cycle life and capacity even at the high C-rate of 3 A g, with a high energy efficiency of 98%, regardless of the differences in the size of chloroaluminate anions.

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