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Electrochemical performance of nanospheric glucose derived hard carbon based electrodes, specially derived from D-glucose via hydrothermal carbonization and subsequent pyrolysis at 1100 • C, has been studied in 1 M NaClO 4 propylene carbonate electrolyte. High Na + electroreduction and Na oxidation peaks were observed in cyclic voltammograms. Galvanostatic charge/discharge measurements demonstrated high specific capacity, over 300 mAh g −1 for the first cycle. After 200 th cycle, a specific capacity of 160 mAh g −1 (at 50 mA g −1 cycling rate) has been calculated for the nanospheric hard carbon based half-cells. Raman spectroscopy, inductively coupled plasma mass spectrometry and energy-dispersive X-ray spectroscopy data indicated accumulation (adsorption/absorption) of Na onto/into the electrochemically polarized porous nanospheric hard carbon material. Impedance data demonstrated that electrode potential has a noticeable influence on the total polarization, and charge transfer resistance as well as on the mass transfer characteristics at the carbon|(1 M NaClO 4 + propylene carbonate) electrolyte interface.Lithium-ion batteries (LIBs) have been studied and used extensively for electric vehicle and smart grid applications. 1 Lithium (Li) is the lightest metallic element and lithium electrochemistry has many advantages such as wide voltage region (up to 4 V), high energy density (250-730 Wh L −1 ), high specific power (approximately 250-340 W kg −1 ) and superior shelf life over a wide temperature range (−20 to 70 • C). 1-7 Li-ion small ionic radius is highly beneficial for mass-transfer step kinetic characteristics, especially in layered solids. However, limited availability and high cost of Li is an increasing constraint when these batteries are deployed and applied on a large scale. Sodium-ion batteries are considered as promising alternative devices to lithium-ion energy storage systems, since sodium (Na) is an abundant and inexpensive element. 1 With growing global energy issues in the 21 st century, sodium-ion electrochemistry has emerged as an attractive alternative energy storage technology to replace LIBs because of sodium abundance and inexpensive raw materials that lower the production cost of sodium-based electrode materials and devices.Sodium-ion batteries (NIBs) utilize similar electrode materials to the ones employed in LIBs; however, the intercalation/accumulation of Na-ion chemistry is slightly different because the Na + ion occupies 1.02 Å in an octahedral coordination site, which is larger than that of Li + (0.76 Å in an octahedral coordination site). 2,3 The choice of sodium is also favored from an electrochemical standpoint as it is characterized by a highly negative redox potential and low electrochemical equivalent (0.86 g (A h) −1 ). 1 While Na intercalation cathode materials are gaining attention, 4-9 recent studies have focused on the systematic development of negative electrode materials. 10-13 Unlike lithiumion batteries, sodium-ion batteries cannot use graphite materials as negative el...

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Mechanisms of ion insertion in hard carbon and the corresponding structural impact on the graphene layer.