Browsing by Author "Yu, Liang"
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Item Open Access Facile synthesis of high-surface-area nanoporous carbon from biomass resources and its application in supercapacitors(Royal Society of Chemistry, 2018-01-09) Yao, Yuechao; Zhang, Qi; Liu, Peng; Yu, Liang; Huang, Lin; Zeng, Shao-Zhong; Liu, Lijia; Zenga, Xierong; Zou, JizhaoIt is critical for nanoporous carbons to have a large surface area, and low cost and be readily available for challenging energy and environmental issues. The pursuit of all three characteristics, particularly large surface area, is a formidable challenge because traditional methods to produce porous carbon materials with a high surface area are complicated and expensive, frequently resulting in pollution (commonly from the activation process). Here we report a facile method to synthesize nanoporous carbon materials with a high surface area of up to 1234 m2 g−1 and an average pore diameter of 0.88 nm through a simple carbonization procedure with carefully selected carbon precursors (biomass material) and carbonization conditions. It is the high surface area that leads to a high capacitance (up to 213 F g−1 at 0.1 A g−1) and a stable cycle performance (6.6% loss over 12 000 cycles) as shown in a three-electrode cell. Furthermore, the high capacitance (107 F g−1 at 0.1 A g−1) can be obtained in a supercapacitor device. This facile approach may open a door for the preparation of high surface area porous carbons for energy storage.Item Open Access Microwave-assisted rapid preparation of hollow carbon nanospheres@TiN nanoparticles for lithium-sulfur batteries(Royal Society of Chemistry, 2018-11-02) Tu, Jianxin; Li, HeJun; Zou, Jizhao; Zeng, Shao-Zhong; Zhang, Qi; Yu, Liang; Zenga, XierongHighly conductive titanium nitride (TiN) has a strong anchoring ability for lithium polysulfides (LiPSs). However, the complexity and high cost of fabrication limit their practical applications. Herein, a typical structure of hollow carbon nanospheres@TiN nanoparticles (HCNs@TiN) was designed and successfully synthesized via a microwave reduction method with the advantages of economy and efficiency. With unique structural and outstanding functional behavior, HCN@TiN-S hybrid electrodes display not only a high initial discharge capacity of 1097.8 mA h g−1 at 0.1C, but also excellent rate performance and cycling stability. After 200 cycles, a reversible capacity of 812.6 mA h g−1 is still retained, corresponding to 74% capacity retention of the original capacity and 0.13% decay rate per cycle, which are much better than those of HCNs-S electrodes.Item Open Access Ultrahigh-content nitrogen-decorated nanoporous carbon derived from metal organic frameworks and its application in supercapacitors(Elsevier, 2018-04-03) Zou, Jizhao; Liu, Peng; Huang, Lin; Zhang, Qi; Lan, Tongbin; Zeng, Shao-Zhong; Zeng, Xierong; Yu, Liang; Liu, Shiyu; Wu, Hongliang; Tu, Wenxuan; Yao, YuechaoSingle electric double-layer capacitors cannot meet the growing demand for energy due to their insufficient energy density. Generally speaking, the supercapacitors introduced with pseudo-capacitance by doping heteroatoms (N, O) in porous carbon materials can obtain much higher capacitance than electric double-layer capacitors. In view of above merits, in this study, nanoporous carbon materials with ultrahigh N enrichment (14.23 wt%) and high specific surface area (942 m2 g−1) by in situ introduction of N-doped MOF (ZTIF-1, Organic ligands 5-methyltetrazole/C2H4N4) were produced. It was found that as supercapacitors' electrode materials, these nanoporous carbons exhibit a capacitance as high as 272 F g-1 at 0.1 A g−1, and an excellent cycle life (almost no attenuation after 10,000 cycles.). Moreover, the symmetric supercapacitors were assembled to further investigate the actual capacitive performance, and the capacitance shows up to 154 F g-1 at 0.1 A g−1. Such excellent properties may be attributed to a combination of a high specific surface area, ultrahigh nitrogen content and hierarchically porous structure. The results shown in this study fully demonstrate that the nanoporous carbon materials containing ultrahigh nitrogen content can be used as a potential electrode material in supercapacitors.Item Open Access A universal strategy to prepare sulfur-containing polymer composites with desired morphologies for lithium−sulfur batteries(American Chemical Society, 2018-06-06) Zeng, Shao-Zhong; Zeng, Xierong; Tu, Wenxuan; Huang, Haitao; Yu, Liang; Yao, Yuechao; Jin, Nengzhi; Zhang, Qi; Zou, JizhaoLithium–sulfur (Li–S) batteries are probably the most promising candidates for the next-generation batteries owing to their high energy density. However, Li–S batteries face severe technical problems where the dissolution of intermediate polysulfides is the biggest problem because it leads to the degradation of the cathode and the lithium anode, and finally the fast capacity decay. Compared with the composites of elemental sulfur and other matrices, sulfur-containing polymers (SCPs) have strong chemical bonds to sulfur and therefore show low dissolution of polysulfides. Unfortunately, most SCPs have very low electron conductivity and their morphologies can hardly be controlled, which undoubtedly depress the battery performances of SCPs. To overcome these two weaknesses of SCPs, a new strategy was developed for preparing SCP composites with enhanced conductivity and desired morphologies. With this strategy, macroporous SCP composites were successfully prepared from hierarchical porous carbon. The composites displayed discharge/charge capacities up to 1218/1139, 949/922, and 796/785 mA h g–1 at the current rates of 5, 10, and 15 C, respectively. Considering the universality of this strategy and the numerous morphologies of carbon materials, this strategy opens many opportunities for making carbon/SCP composites with novel morphologies.