TY  - JOUR
A1  - Chen, Lu
A1  - Yan, Runyu
A1  - Oschatz, Martin
A1  - Jiang, Lei
A1  - Antonietti, Markus
A1  - Xiao, Kai
T1  - Ultrathin 2D graphitic carbon nitride on metal films
BT  - underpotential sodium deposition in adlayers for sodium-ion batteries
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - Efficient and low-cost anode materials for the sodium-ion battery are highly desired to enable more economic energy storage. Effects on an ultrathin carbon nitride film deposited on a copper metal electrode are presented. The combination of effects show an unusually high capacity to store sodium metal. The g-C3N4 film is as thin as 10 nm and can be fabricated by an efficient, facile, and general chemical-vapor deposition method. A high reversible capacity of formally up to 51 Ah g(-1) indicates that the Na is not only stored in the carbon nitride as such, but that carbon nitride activates also the metal for reversible Na-deposition, while forming at the same time an solid electrolyte interface layer avoiding direct contact of the metallic phase with the liquid electrolyte.
KW  - 2D films
KW  - carbon nitride
KW  - chemical vapor deposition
KW  - sodium-ion
KW  - batteries
KW  - underpotential deposition
Y1  - 2020
U6  - https://doi.org/10.1002/anie.202000314
SN  - 1433-7851
SN  - 1521-3773
VL  - 59
IS  - 23
SP  - 9067
EP  - 9073
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Yan, Runyu
A1  - Oschatz, Martin
A1  - Wu, Feixiang
T1  - Towards stable lithium-sulfur battery cathodes by combining physical and chemical confinement of polysulfides in core-shell structured nitrogen-doped carbons
JF  - Carbon
N2  - Despite intensive research on porous carbon materials as hosts for sulfur in lithium-sulfur battery cathodes, it remains a problem to restrain the soluble lithium polysulfide intermediates for a long-term cycling stability without the use of metallic or metal-containing species. Here, we report the synthesis of nitrogen-doped carbon materials with hierarchical pore architecture and a core-shell-type particle design including an ordered mesoporous carbon core and a polar microporous carbon shell. The initial discharge capacity with a sulfur loading up to 72 wt% reaches over 900 mA h g(sulf)(ur)(-1) at a rate of C/2. Cycling performance measured at C/2 indicates similar to 90% capacity retention over 250 cycles. In comparison to other carbon hosts, this architecture not only provides sufficient space for a high sulfur loading induced by the high-pore-volume particle core, but also enables a dual effect of physical and chemical confinement of the polysulfides to stabilize the cycle life by adsorbing the soluble intermediates in the polar microporous shell. This work elucidates a design principle for carbonaceous hosts that is capable to provide simultaneous physical-chemical confinement. This is necessary to overcome the shuttle effect towards stable lithium-sulfur battery cathodes, in the absence of additional membranes or inactive metal-based anchoring materials.
KW  - lithium-sulfur battery
KW  - sulfur
KW  - porous carbon
KW  - cathode
KW  - polysulfides
Y1  - 2020
U6  - https://doi.org/10.1016/j.carbon.2020.01.046
SN  - 0008-6223
SN  - 1873-3891
VL  - 161
SP  - 162
EP  - 168
PB  - Elsevier Science
CY  - Amsterdam [u.a.]
ER  -