Electrochemical Na Insertion and Solid Electrolyte Interphase for Hard‐Carbon Electrodes and Application to Na‐Ion Batteries

Abstract

Recently, lithium-ion batteries have been attracting more interest for use in automotive applications. Lithium resources are confi rmed to be unevenly distributed in South America, and the cost of the lithium raw materials has roughly doubled from the fi rst practical application in 1991 to the present and is increasing due to global demand for lithium-ion accumulators. Since the electrochemical equivalent and standard potential of sodium are the most advantageous after lithium, sodium based energy storage is of great interest to realize lithium-free high energy and high voltage batteries. However, to the best of our knowledge, there have been no successful reports on electrochemical sodium insertion materials for battery applications; the major challenge is the negative electrode and its passivation. In this study, we achieve high capacity and excellent reversibility sodium-insertion performance of hard-carbon and layered NaNi 0.5 Mn 0.5 O 2 electrodes in propylene carbonate electrolyte solutions. The structural change and passivation for hard-carbon are investigated to study the reversible sodium insertion. The 3-volt secondary Na-ion battery possessing environmental and cost friendliness, Na + -shuttlecock hard-carbon/NaNi 0.5 Mn 0.5 O 2 cell, demonstrates steady cycling performance as next generation secondary batteries and an alternative to Li-ion batteries.

Aromatic porous-honeycomb electrodes for a sodium-organic energy storage device

“…The initial OCV is B2.8 V versus Na/Na þ , and therefore, the p-dopable and n-dopable regions are above and below 2.8 V versus Na/Na þ , respectively. We used 1 M NaClO 4 in PC as an electrolyte due to its high stability in the Na-ion battery system 16 . For a high current density of 5 A g -1 , the BPOE can provide a specific capacity of B50 mAh g -1 .…”

“…The importance of the selection of the electrolyte is evident by comparing two different electrolytes for the cycle stability test. Both 1 M NaClO 4 in ethylene carbonate (EC): diethyl carbonate (DEC) (1:1) and 1 M NaClO 4 in PC were reported as stable electrolytes for the Na-ion battery system up to 100 cycles 16 . In contrast to 1 M NaClO 4 in PC, the cell with 1 M NaClO 4 in EC:DEC begins to show a degradation from about 200 cycles.…”

“…There is an urgent need for alternative energy storage devices with a performance comparable to, or better than rechargeable lithium batteries. One possible approach is to use sodium as an alternative charge carrier [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] to lithium, as the cost of sodium carbonate (Na 2 CO 3 ), for example, is only 3% of Li 2 CO 3 (ref. 5).…”

MoS2/Graphene Composite Paper for Sodium-Ion Battery Electrodes

“…[15][16][17][18] For carbon-based electrode materials, much of the emphasis has been on hard carbons due to large interlayer spacing and disordered structure. [19][20][21][22][23][24][25] For example, hard carbon prepared from pyrolyzed glucose, carbon black, and carbon microspheres have been shown to exhibit initial reversible capacities of 300 mAhg -1 , 200 mAhg -1 , and 285 mAhg -1 , respectively in a Na-ion cell. [15][16][17] More recently, another hard carbon material that could deliver a reversible capacity of more than 200 mAhg -1 over 100 cycles has been reported.…”

“…[15][16][17] More recently, another hard carbon material that could deliver a reversible capacity of more than 200 mAhg -1 over 100 cycles has been reported. 22,25 However, these studies were conducted on traditional anode architecture (prepared through slurry coating of active material on metallic current collector foil and the capacities reported were with respect to the active material only), either at low cycling current rates or at elevated temperatures. Overall, new electrode design and concepts based on chemistry other than alloying and ion intercalation must also be explored to realize improved performance in Na-ion batteries under normal operating conditions.…”