Battery chemistry based on earth-abundant elements has great potential for the development of cost-effective, large-scale energy storage systems. Herein, we report, for the first time, that maricite NaFePO 4 can function as an excellent cathode material for Na ion batteries, an unexpected result since it has been regarded as an electrochemically inactive electrode for rechargeable batteries. Our investigation of the Na re-(de)intercalation mechanism reveals that all Na ions can be deintercalated from the nano-sized maricite NaFePO 4 with simultaneous transformation into amorphous FePO 4 . Our quantum mechanics calculations show that the underlying reason for the remarkable electrochemical activity of NaFePO 4 is the significantly enhanced Na mobility in the transformed phase, which is $one fourth of the hopping activation barrier. Maricite NaFePO 4 , fully sodiated amorphous FePO 4 , delivered a capacity of 142 mA h g À1 (92% of the theoretical value) at the first cycle, and showed outstanding cyclability with a negligible capacity fade after 200 cycles (95% retention of the initial cycle).The demand for large-scale energy storage systems (EESs) has prompted considerable effort in the development of new types of batteries with cost-effective and sustainable properties. While the high cost of current Li ion batteries (LIBs) remains one of the major hurdles towards large-scale energy storage applications, 1-12 battery chemistry based on earth-abundant elements offers a feasible solution. Recently, Na ion batteries (NIBs) have been considered as a promising alternative to LIBs since the underlying electrochemical reaction is similar to that of LIBs, but is based on the unlimited resources of Na from seawater. [13][14][15][16][17][18][19][20] The use of redox chemistry using earth abundant transition metals would provide the optimal combination with Na electrochemistry further highlighting the advantage of NIBs.In recent years, considerable research has been carried out on Fe-based electrode materials for use in NIBs. Broader contextWe report, for the rst time, that maricite NaFePO 4 can function as an excellent cathode material for Na ion batteries, an unexpected result since it has been regarded as an electrochemically inactive electrode for rechargeable batteries. Our investigation of the Na re-(de)intercalation mechanism reveals that all Na ions can be deintercalated from the nanosized maricite NaFePO 4 with simultaneous transformation into amorphous FePO 4 . Our quantum mechanics calculations show that the underlying reason for the remarkable electrochemical activity of NaFePO 4 is the signicantly enhanced Na mobility in the transformed phase, which is $one fourth of the hopping activation barrier. Maricite NaFePO 4 , fully sodiated amorphous FePO 4 , delivered a capacity of 142 mA h g À1 (92% of the theoretical value) at the rst cycle, and showed outstanding cyclability with a negligible capacity fade aer 200 cycles (95% retention of the initial cycle).540 | Energy Environ. Sci., 2015, 8, 540-545This jour...

The facile synthesis of silicon nanotubes using a surface sol-gel reaction on pyridine nanowire templates is reported and their performance for energy storage is investigated. Organic-inorganic hybrid pyridine/silica core-shell nanowires prepared using surface sol-gel reaction were converted to silica nanotubes by pyrolysis in air; this was followed by the reduction to silicon nanotubes via magnesiothermic reaction. The electrochemical activity of the obtained silicon nanotubes showed excellent cycle stability, suggesting that the hollow one-dimensional structure would be a good candidate for a high-capacity anode for a lithium ion battery.

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Phase-change random access memory (PRAM) is considered as one of the most promising candidates for future memories because of its good scalability and cost-effectiveness [1]. Besides implementations with standard interfaces like NOR flash or LPDDR2-NVM, application-oriented approaches using PRAM as main-memory or storage-class memory have been researched [2][3]. These studies suggest that noticeable merits can be achieved by using PRAM in improving power consumption, system cost, etc. However, relatively low chip density and insufficient write bandwidth of PRAMs are obstacles to better system performance. In this paper, we present an 8Gb PRAM with 40MB/s write bandwidth featuring 8Mb sub-array core architecture with 20nm diode-switched PRAM cells [4]. When an external high voltage is applied, the write bandwidth can be extended as high as 133MB/s.