Browsing by Author "Zeng, Xierong"

Now showing 1 - 12 of 12
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    Construction of porous hierarchical NiCo2S4 toward high rate performance supercapacitor
    (Springer, 2019-11-11) Zhao, Fenglin; Huang, Wanxia; Sial, Muhammad Aurang Z. G.; Xie, Dong; Wu, Hongliang; Zhang, Qi; Zou, Jizhao; Zeng, Xierong
    Developing high-performance supercapacitors is an effective way to satisfy the ever-increasing energy storage demand for emerging devices, but the inferior rate performance of battery-type supercapacitors limits their large-scale utilization. Herein, porous hierarchical nickel cobalt sulfide (NiCo2S4) was constructed by a novel strategy that the synthesized nickel cobalt oxide nanosheets as chemical template for hydrothermal method. Furthermore, the backbone of nickel cobalt oxide nanosheets can finally convert to NiCo2S4, which both plays the role of matrix to buffer the volume variation and enhances entire conductivity. Benefiting from high specific area (79.9 m2 g−1), suitable nanopores for KOH electrolyte, high conductivity, and multiple Co/Ni valence, the hierarchical NiCo2S4 electrode delivers a high specific capacity of 1035.1 F g−1 at the current density of 1 A g−1, and an ultrahigh rate performance of 80.9% capacitance retention at 20 A g−1 was obtained. The assembled asymmetric supercapacitor device could achieve the maximum capacity of 102.4 F g−1 at 5 mV s−1 and maintain at 80.5 F g−1 at 50 mV s−1, indicating its superior rate ability. In addition, the highest energy density of 35.4 Wh kg−1 can be obtained at a power density of 0.4 kW kg−1. These results indicate that the porous hierarchical NiCo2S4 could be served as high rate performance electrode materials for advanced supercapacitors.
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    Facile synthesis of 2D ultrathin and ultrahigh specific surface hierarchical porous carbon nanosheets for advanced energy storage
    (Elsevier, 2019-09-10) Yao, Yuechao; Xiao, Zunqin; Liu, Peng; Zhang, Shengjiao; Niu, Yuan; Wu, Hongliang; Liu, Shiyu; Tu, Wenxuan; Luo, Qi; Sial, Muhammad Aurang Zeb Gul; Zeng, Shao-Zhong; Zhang, Qi; Zou, Jizhao; Zeng, Xierong; Zhang, Wenjing
    Two dimensional (2D) porous carbon nanosheets (CNS) have attracted tremendous research interests in energy storage and conversion, such as supercapacitors (SCs) and lithium-sulfur batteries, because of their unique micromorphology, chemical stability and high specific surface area (SSA). Rational design and facile scalable synthesis of CNS with high SSA, low cost and ultrathin nanosheet structure is highly desired but hitherto remains a big challenge. Here, we report a novel synthesis method of 2D hierarchical porous CNS with ultrahigh SSA (2687 m2 g−1) and ultrathin structure by directly pyrolysing and activating a unique and abundant biomass sheet. The electrochemical characterisations show that the prepared CNS-4-1 materials as electrodes creates a good energy-storage capability, with the energy density being 91 Wh kg−1 for symmetric SCs in ionic liquids, which is the highest in the reported biomass-derived CNS materials for SCs applications so far. Besides, the CNS-5-1 also exhibits a high initial capacity of 1078 mAh g−1 at 0.1 C when it acted as a sulfur hosting material for lithium-sulfur batteries. More importantly, it also shows a 586 mAh g−1 reversible capacity and an approaching 100% coulombic efficiency after 500 cycles at a high rate of 1 C. These superior electrochemical properties of the CNS are mainly attributed to their unique 2D ultrathin nanosheet structure, large SSA, and reasonable hierarchical porous structure. This work not only provides a new strategy to fabricate the ultrathin CNS in large scale and low cost but also enlarges CNS materials potential applications in energy storage.
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    Facile synthesis of TiN nanocrystals/graphene hybrid to chemically suppress the shuttle effect for lithium-sulfur batteries
    (Elsevier, 2020-01-08) Tu, Jianxin; Li, Hejun; Lan, Tongbin; Zeng, Shao-Zhong; Zou, Jizhao; Zhang, Qi; Zeng, Xierong
    Herein, we present a microwave reduction strategy for the synthesis of reduced-graphene-oxide (rGO) supported TiN nanoparticle hybrid (TiN/rGO) under N2 atmosphere. The method involves GO reduction, metal oxide reduction and nitridation reaction in one single step. Due to TiN high conductivity and good interfacial affinity between it and lithium polysulfides (LiPSs), the prepared TiN/rGO-Sulfur (TiN/rGO-S) cathodes demonstrate rapid charge transfer, lower polarization, faster surface redox reaction kinetic and enhanced stability cycling performance than rGO-Sulfur (rGO-S) and TiO2/rGO-Sulfur (TiO2/rGO-S) cathodes. The initial capacity reaches 1197.6 mA h g−1 with a reversible capacity of 888.7 mA h g−1 being retained after 150 cycles at 0.1 C.
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    Facile synthesis of ultrahigh-surface-area hollow carbon nanospheres and their application in lithium-sulfur batteries
    (Wiley-VCH, 2017-12-13) Zeng, Shao-Zhong; Yao, Yuechao; Huang, Lin; Wu, Hongliang; Peng, Biaolin; Zhang, Qi; Li, Xiaohua; Yu, Liang; Liu, Shiyu; Tu, Wenxuan; Lan, Tongbin; Zeng, Xierong; Zou, Jizhao
    Hollow carbon nanospheres (HCNs) with specific surface areas up to 2949 m2 g−1 and pore volume up to 2.9 cm3 g−1 were successfully synthesized from polyaniline‐co‐polypyrrole hollow nanospheres by carbonization and CO2 activation. The cavity diameter and wall thickness of HCNs can be easily controlled by activation time. Owing to their large inner cavity and enclosed structure, HCNs are desirable carriers for encapsulating sulfur. To better understand the effects of pore characteristics and sulfur contents on the performances of lithium‐sulfur batteries, three composites of HCNs and sulfur are prepared and studied in detail. The composites of HCNs with moderate specific surface areas and suitable sulfur content present a better performance. The first discharge capacity of this composite reaches 1401 mAh g−1 at 0.2 C. Even after 200 cycles, the discharge capacity remains at 626 mAh g−1.
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    Giant electric energy density in epitaxial lead-free thin films with coexistence of ferroelectrics and antiferroelectrics
    (Wiley, 2015-04-11) Peng, Biaolin; Zhang, Qi; Li, Xing; Sun, Tieyu; Fan, Huiqing; Ke, Shanming; Ye, Mao; Wang, Yu; Lu, Wei; Niu, Hanben; Scott, James F.; Zeng, Xierong; Huang, Haitao
    Ferroelectrics/antiferroelectrics with high dielectric breakdown strength have the potential to store a great amount of electrical energy, attractive for many modern applications in electronic devices and systems. Here we demonstrate that a giant electric energy density (154 J×cm-3, 3 times the highest value of lead-based systems and 5 times the value of the best dielectric/ferroelectric polymer), together with the excellent fatigue-free property, good thermal stability and high efficiency, is realized in pulsed laser deposited (Bi1/2Na1/2)0.9118La0.02Ba0.0582(Ti0.97Zr0.03)O3 (BNLBTZ) epitaxial lead-free relaxor thin films with the coexistence of ferroelectric (FE) and antiferroelectric (AFE) phases. This is endowed by high epitaxial quality, great relaxor dispersion and the coexistence of the FE/AFE phases near the morphotropic phase boundary (MPB). The giant energy storage effect of the BNLBTZ lead-free relaxor thin films may make a great impact on the modern energy storage technology.
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    High dielectric tunability, electrostriction strain and electrocaloric strength at a tricritical point of tetragonal, rhombohedral and pseudocubic phases
    (Elsevier, 2015-06-16) Peng, Biaolin; Zhang, Qi; Li, Tieyu; Ke, Shanming; Ye, Mao; Wang, Yu; Niu, Hanben; Zeng, Xierong; Fan, Huiqing; Huang, Haitao
    A relaxor ferroelectric Pb(Ni1/3Nb2/3)0.5Zr0.15Ti0.35O3 (PNNZT) ceramic was reported, designed upon an idea that the composition is selected to near a tricritical point of tetragonal, rhombohedral and pseudocubic phases. High dielectric tunability of 67%, simultaneously with high electrostriction strain of 0.319% and high electrocaloric strength (ΔT/ΔE) of 32.5 mK cm/kV are achieved, which make it a promising multifunctional material for applications in dielectric tunable, precisely controlled and electric refrigeration devices. This is endowed by the low energy barrier among the transitions of phases and strong relaxor ferroelectric activities around the tricritical point. This work provides a guide for the design of multifunctional ferroelectric materials and can promote the development of other multifunctional ferroic materials.
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    High-performance supercapacitors based on hierarchically porous carbons with a three-dimensional conductive network structure
    (Royal Society of Chemistry, 2019-03-27) Zou, Jizhao; Tu, Wenxuan; Zeng, Shao-Zhong; Yao, Yuechao; Zhang, Qi; Wu, Hongliang; Lan, Tongbin; Liua, Shiyu; Zeng, Xierong
    Clews of polymer nanobelts (CsPNBs) have the advantages of inexpensive raw materials, simple synthesis and large output. Novel clews of carbon nanobelts (CsCNBs) have been successfully prepared by carbonizing CsPNBs and by KOH activation subsequently. From the optimized process, CsCNBs*4, with a specific surface area of 2291 m2 g−1 and a pore volume of up to 1.29 cm3 g−1, has been obtained. Fundamentally, the CsCNBs possess a three-dimensional conductive network structure, a hierarchically porous framework, and excellent hydrophilicity, which enable fast ion diffusion through channels and a large enough ion adsorption/desorption surface to improve electrochemical performance of supercapacitors. The product exhibits a high specific capacitance of 327.5 F g−1 at a current density of 0.5 A g−1 in a three-electrode system. The results also reveal a high-rate capacitance (72.2% capacitance retention at 500 mV s−1) and stable cycling lifetime (95% of initial capacitance after 15 000 cycles). Moreover, CsCNBs*4 provides a high energy density of 29.8 W h kg−1 at a power density of 345.4 W kg−1 in 1 M tetraethylammonium tetrafluoroborate/acetonitrile (TEABF4/AN) electrolyte. These inspiring results imply that this carbon material with a three-dimensional conductive network structure possesses excellent potential for energy storage.
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    Large Energy Storage Density and High Thermal Stability in a Highly Textured (111)-Oriented Pb0.8Ba0.2ZrO3 Relaxor Thin Film with the Coexistence of Antiferroelectric and Ferroelectric Phases
    (American Chemical Society, 2015-05-21) Peng, Biaolin; Zhang, Qi; Li, Xing; Sun, Tieyu; Fan, Huiqing; Ke, Shanming; Ye, Mao; Wang, Yu; Lu, Wei; Niu, Hanben; Zeng, Xierong; Huang, Haitao
    A highly textured (111)-oriented Pb0.8Ba0.2ZrO3 (PBZ) relaxor thin film with the coexistence of antiferroelectric (AFE) and ferroelectric (FE) phases was prepared on a Pt/TiOx/SiO2/Si(100) substrate by using a sol-gel method. A large recoverable energy storage density of 40.18 J/cm3 along with an efficiency of 64.1% was achieved at room temperature. Over a wide temperature range of 250 K (from room temperature to 523 K), the variation of the energy density is within 5%, indicating a high thermal stability. The high energy storage performance was endowed by a large dielectric breakdown strength, great relaxor dispersion, highly textured orientation, and the coexistence of FE and AFE phases. The PBZ thin film is believed to be an attractive material for applications in energy storage systems over a wide temperature range (Graph Presented).
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    Nitrogen-doped micropores binder-free carbon-sulphur composites as the cathode for long-life lithium-sulphur batteries
    (Elsevier, 2018-08-10) Yao, Yuechao; Liu, Peng; Zhang, Qi; Zeng, Shao-Zhong; Chen, Shuangshuang; Zou, Guangjin; Zou, Jizhao; Zeng, Xierong; Li, Xiaohua
    Nitrogen-doped micropores-contained carbon nanofibres (NMCNFs) were prepared by carbonizing ZIF-8 grown in liquid-phase along with electrospinning. When NMCNFs act as sulphur host materials in lithium–sulphur batteries, NMCNFs can retard the shuttle effect and dissolution of polysulfides through the synergic action of effective physical confinement to micropores and nitrogen surface chemical absorption. NMCNFs show a capacity up to 636 mAh g−1 after 500 cycles against Li anode.
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    Optimized synthesis of ultrahigh-surface-area and oxygen-doped carbon nanobelts for high cycle-stability lithium-sulfur batteries
    (Electrochemical Society, 2019-10-14) Zou, Jizhao; Niu, Yuan; Tu, Wenxuan; Zhang, Qi; Yao, Yuechao; Zeng, Shao-Zhong; Lan, Tongbin; Wu, Hongliang; Zeng, Xierong; Zeng, Xierong
    Hierarchical clews of carbon nanobelts (CsCNBs) with ultrahigh specific surface area (2300 m2 g−1) and large pore volume (up to 1.29 cm3 g−1) has been successfully fabricated through carbonization and KOH activation of phenolic resin based nanobelts. The product possesses hierarchically porous structure, three-dimensional conductive network framework, and polar oxygen-rich groups, which are very befitting to load sulfur leading to excellent cycling stability of lithium-sulfur batteries. The composites of CsCNBs/sulfur exhibit an ultrahigh initial discharge capacity of 1245 mA h g−1 and ultralow capacity decay rate as low as 0.162% per cycle after 200 cycles at 0.1 C. Even at high current rate of 4 C, the cells still display a high initial discharge capacity (621 mA h g−1) and ultralow capacity decay rate (only 0.039% per cycle) after 1000 cycles. These encouraging results indicate that polar oxygen-containing functional groups are important for improving the electrochemical performance of carbons. The oxygen-doped carbon nanobelts have excellent energy storage potential in the field of energy storage.
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    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, Yuechao
    Single 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.
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    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, Jizhao
    Lithium–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.