N, O-codoped hierarchical porous carbons derived from algae for high-capacity supercapacitors and battery anodes

By Yu, Wenhua; Wang, Huanlei; Liu, Shuang; Mao, Nan; Liu, Xiao; Shi, Jing; Liu, Wei; Chen, Shougang; Wang, Xin
Published in J. Mater. Chem. A The Royal Society of Chemistry 2016

Abstract

Nitrogen and oxygen codoped hierarchical porous carbons have been synthesized by using a direct carbonization/activation procedure of biomass algae - Enteromorpha. The proposed procedure allowed us to produce carbons with high surface area (up to 2073 m2 g-1), sponge-like 3D interconnected structure, combined macro/meso/micropores, and rich N (0.64-0.85 at%) and O (11.36-12.24 at%) doping. The application of the produced carbons in supercapacitors based on an ionic liquid electrolyte showed a high specific capacitance of 201 F g-1 (10.7 [small mu ]F cm-2) at 1 A g-1 and 20 [degree]C, a capacitance retention ratio of 61% at 100 A g-1 and a capacitance loss of 9% after 10 000 cycles. The devices were able to deliver an energy density of 24 or 35 W h kg-1 (on an active mass normalized basis) at an extremely high power density of 60 kW kg-1 at 20 or 60 [degree]C. The application of the produced carbons in a lithium-ion battery anode based on the LiPF6 electrolyte exhibited a high specific capacity of 1347-1709 mA h g-1, a good initial coulombic efficiency of 61-64%, and a good cyclability up to 500 cycles. We believe that this simple precursor-synthesis route offers excellent potential for facile large-scale material production for supercapacitors and lithium ion batteries.

Read Article » Back