Silk could be new 'green' material for next-generation batteries

Silk could be new 'green' material for next-generation batteries

Lithium-ion batteries have enabled many of today's electronics, from portable gadgets to electric cars. But much to the frustration of consumers, none of these batteries last long without a recharge. Now scientists report in the journal ACS Nano the development of a new, "green" way to boost the performance of these batteries—with a material derived from silk.

Chuanbao Cao and colleagues note that carbon is a key component in commercial Li-ion energy storage devices including batteries and supercapacitors. Most commonly, graphite fills that role, but it has a limited energy capacity. To improve the energy storage, manufacturers are looking for an alternative material to replace graphite. Cao's team wanted to see if they could develop such a material using a sustainable source.

The researchers found a way to process natural silk to create carbon-based nanosheets that could potentially be used in . Their material stores five times more lithium than graphite can—a capacity that is critical to improving battery performance. It also worked for over 10,000 cycles with only a 9 percent loss in stability.

The researchers successfully incorporated their material in prototype batteries and supercapacitors in a one-step method that could easily be scaled up, the researchers note.


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More information: Hierarchical Porous Nitrogen-Doped Carbon Nanosheets Derived from Silk for Ultrahigh-Capacity Battery Anodes and Supercapacitors ACS Nano, Article ASAP. DOI: 10.1021/nn506394r

Abstract
Hierarchical porous nitrogen-doped carbon (HPNC) nanosheets (NS) have been prepared via simultaneous activation and graphitization of biomass-derived natural silk. The as-obtained HPNC-NS show favorable features for electrochemical energy storage such as high specific surface area (SBET: 2494 m2/g), high volume of hierarchical pores (2.28 cm3/g), nanosheet structures, rich N-doping (4.7%), and defects. With respect to the multiple synergistic effects of these features, a lithium-ion battery anode and a two-electrode-based supercapacitor have been prepared. A reversible lithium storage capacity of 1865 mA h/g has been reported, which is the highest for N-doped carbon anode materials to the best of our knowledge. The HPNC-NS supercapacitor's electrode in ionic liquid electrolytes exhibit a capacitance of 242 F/g and energy density of 102 W h/kg (48 W h/L), with high cycling life stability (9% loss after 10 000 cycles). Thus, a high-performance Li-ion battery and supercapacitors were successfully assembled for the same electrode material, which was obtained through a one-step and facile large-scale synthesis route. It is promising for next-generation hybrid energy storage and renewable delivery devices.

Journal information: ACS Nano

Citation: Silk could be new 'green' material for next-generation batteries (2015, March 11) retrieved 4 April 2020 from https://phys.org/news/2015-03-silk-green-material-next-generation-batteries.html
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