Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hi...Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hindered by sluggish kinetics and large volume expansion. Herein, N/S co-doped carbon nanocapsule (NSCN) is constructed for superior K+ storage. The NSCN possesses 3D nanocapsule framework with abundant meso/macropores, which guarantees structural robustness and accelerates ions/electrons transportation. The high-level N/S co-doping in carbon matrix not only generates ample defects and active sites for K+ adsorption, but also expands interlayer distance for facile K+ intercalation/deintercalation. As a result, the NSCN electrode delivers a high reversible capacity (408 mAh g^(−1) at 0.05 A g^(−1)), outstanding rate capability (149 mAh g^(−1) at 5 A g^(−1)) and favorable cycle stability (150m Ah g^(−1) at 2 A g^(−1) after 2000 cycles). Ex situ TEM, Raman and XPS measurements demonstrate the excellent stability and reversibility of NSCN electrode during potassiation/depotassiation process. This work provides inspiration for the optimization of energy storage materials by structure and doping engineering.展开更多
The adsorption of hydrogen molecule on the external surface of pure 0120 nanocapsule and endohedrallyH2 @C120 complex has been examined using the density functional theory calculations. Several different bonding confi...The adsorption of hydrogen molecule on the external surface of pure 0120 nanocapsule and endohedrallyH2 @C120 complex has been examined using the density functional theory calculations. Several different bonding configu- rations are considered for the hydrogen molecule approaching the outer surface of the considered nanocages. It has been found that the adsorbed H2 molecule bound weakly to the outer surface of the pure C1~0 nanocapsules in agreement with the recent experimental and theoretical results while, it prefers to be adsorbed rather strongly on the side wall of the endohedrally /-/2@C120 complex. The adsorption of a single layer and bi-layer of two tt2 molecules on the most stable states of the considered H2@C120 complex appears to be feasible, although the molecules of the second layer are weakly bound. Furthermore, it is found that the formation of 100% coverage is favorable thermodynamically, which corresponds to about 20% by weight storage of 1-12 molecules. Thus, surprisingly, we arrive at the prediction that the C120 nanocapsules can be implemented as a novel material for energy storage.展开更多
基金the financial supports from the National Natural Science Foundation of China(Grant Nos.51872005,U1508201,52072002)。
文摘Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hindered by sluggish kinetics and large volume expansion. Herein, N/S co-doped carbon nanocapsule (NSCN) is constructed for superior K+ storage. The NSCN possesses 3D nanocapsule framework with abundant meso/macropores, which guarantees structural robustness and accelerates ions/electrons transportation. The high-level N/S co-doping in carbon matrix not only generates ample defects and active sites for K+ adsorption, but also expands interlayer distance for facile K+ intercalation/deintercalation. As a result, the NSCN electrode delivers a high reversible capacity (408 mAh g^(−1) at 0.05 A g^(−1)), outstanding rate capability (149 mAh g^(−1) at 5 A g^(−1)) and favorable cycle stability (150m Ah g^(−1) at 2 A g^(−1) after 2000 cycles). Ex situ TEM, Raman and XPS measurements demonstrate the excellent stability and reversibility of NSCN electrode during potassiation/depotassiation process. This work provides inspiration for the optimization of energy storage materials by structure and doping engineering.
文摘The adsorption of hydrogen molecule on the external surface of pure 0120 nanocapsule and endohedrallyH2 @C120 complex has been examined using the density functional theory calculations. Several different bonding configu- rations are considered for the hydrogen molecule approaching the outer surface of the considered nanocages. It has been found that the adsorbed H2 molecule bound weakly to the outer surface of the pure C1~0 nanocapsules in agreement with the recent experimental and theoretical results while, it prefers to be adsorbed rather strongly on the side wall of the endohedrally /-/2@C120 complex. The adsorption of a single layer and bi-layer of two tt2 molecules on the most stable states of the considered H2@C120 complex appears to be feasible, although the molecules of the second layer are weakly bound. Furthermore, it is found that the formation of 100% coverage is favorable thermodynamically, which corresponds to about 20% by weight storage of 1-12 molecules. Thus, surprisingly, we arrive at the prediction that the C120 nanocapsules can be implemented as a novel material for energy storage.
