TY  - JOUR
A1  - Lai, Feili
A1  - Feng, Jianrui
A1  - Heil, Tobias
A1  - Tian, Zhihong
A1  - Schmidt, Johannes
A1  - Wang, Gui-Chang
A1  - Oschatz, Martin
T1  - Partially delocalized charge in Fe-doped NiCo2S4 nanosheet-mesoporous carbon-composites for high-voltage supercapacitors
JF  - Journal of materials chemistry : A, Materials for energy and sustainability
N2  - Unraveling the effect of transition-metal doping on the energy storage properties of bimetallic sulfides remains a grand challenge. Herein, we construct bimetallic sulfide nanosheets and hence deliberately introduce transition-metal doping domains on their surface. The resulting materials show not only an enhanced density of states near the Fermi level but also partially delocalized charge as shown by density functional theory (DFT) calculations. Fe-doped NiCo2S4 nanosheets wrapped on N,S-doped ordered mesoporous carbon (Fe-NiCo2S4@N,S-CMK-3) are prepared, which show an enhanced specific capacitance of 197.8 F g(-1) in ionic liquid-based supercapacitors at a scan rate of 2 mV s(-1). This is significantly higher as compared to the capacitance of 155.2 and 135.9 F g(-1) of non-iron-doped NiCo2S4@N,S-CMK and Fe-NiCo2S4@CMK-3 electrodes, respectively. This result arises from the enhanced ionic liquid polarization effect and transportation ability from the Fe-NiCo2S4 surface and N,S-CMK-3 structure. Furthermore, the importance of matching multi-dimensional structures and ionic liquid ion sizes in the fabrication of asymmetric supercapacitors (ASCs) is demonstrated. As a result, the ASC device exhibits a high energy density of 107.5 W h kg(-1) at a power density of 100 W kg(-1) in a working-voltage window of 4 V when using Fe-NiCo2S4@N,S-CMK-3 and N,S-CMK-3 as positive and negative electrodes, respectively. This work puts forward a new direction to design supercapacitor composite electrodes for efficient ionic liquid coupling.
Y1  - 2019
U6  - https://doi.org/10.1039/c9ta06250e
SN  - 2050-7488
SN  - 2050-7496
VL  - 7
IS  - 33
SP  - 19342
EP  - 19347
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - THES
A1  - Tian, Zhihong
T1  - Oxygen-, Sulfur-doped Novel Porous Carbon-Nitrogen Frameworks by Salt Melt Method
Y1  - 2019
ER  -