کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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4767066 | 1424113 | 2017 | 10 صفحه PDF | دانلود رایگان |
Lithium sulfur (Li-S) batteries possess high theoretical specific capacity (1675 mAh gâ1) and energy density (2567 Wh kgâ1), but are plagued by their poor rate performance. The discovery of new carbon sources, design of novel porous carbon structures, and effective hetero-atom doping of the sulfur matrix are key to overcome this dilemma. In this paper, a boron-doped porous carbon material with a termite nest shape (TNPBC) was obtained from a new carbon source, polyaspartic acid, and borax. Importantly, the doping, activation, and pyrolysis were integrated into one step through a low cost and simple methodology. The borax was essential to formation of a high surface porous architecture and provided boron dopants, which, combined with polyaspartic acid, achieves co-doping (B and N) carbon materials with special porous structures. The simultaneous pore-formation and doping leave an abundance of hetero-atoms exposed on the surface of pores, which enhances the electrostatic interactions between the hetero-atoms and the charged species in the batteries. As a result, the S/TNPBC cathode maintains a stable capacity of 703 mAh gâ1 with an excellent Coulombic efficiency of 101.3% after 120 cycles at 0.1C. Moreover, it exhibits an excellent rate capability with an initial capacity of 650 mAh gâ1 at 0.5C and sustains a capacity of 500 mAh gâ1 after 100 cycles. Furthermore, when TNPBC is used as the anode in a sodium ion battery, an excellent rate capability is achieved. The specific charge capacity is three times greater than without boron doping at 500 mA gâ1. Due to the simple fabrication process and desirable properties of this novel architecture, TNPBC provides a new strategy for enhancing the performance of commercial energy storage devices.
A novel kind of porous boron-doped carbon (TNPBC) with a termite nest structure was synthesized by combining doping, activation, and pyrolysis into one step. Using the synthesized material as a sulfur reservoir, TNPBC effectively relieved the “shuttle effect” commonly found in Li-S electrodes and achieved a decent rate performance in Li-S and sodium ion batteries.181
Journal: Electrochimica Acta - Volume 244, 1 August 2017, Pages 86-95