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1.
Large‐Scale Fabrication of Core–Shell Structured C/SnO2 Hollow Spheres as Anode Materials with Improved Lithium Storage Performance 下载免费PDF全文
Yong Cheng Qian Li Chunli Wang Lianshan Sun Zheng Yi Limin Wang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(47)
Due to the high theoretical capacity as high as 1494 mAh g?1, SnO2 is considered as a potential anode material for high‐capacity lithium–ion batteries (LIBs). Therefore, the simple but effective method focused on fabrication of SnO2 is imperative. To meet this, a facile and efficient strategy to fabricate core–shell structured C/SnO2 hollow spheres by a solvothermal method is reported. Herein, the solid and hollow structure as well as the carbon content can be controlled. Very importantly, high‐yield C/SnO2 spheres can be produced by this method, which suggest potential business applications in LIBs field. Owing to the dual buffer effect of the carbon layer and hollow structures, the core–shell structured C/SnO2 hollow spheres deliver a high reversible discharge capacity of 1007 mAh g?1 at a current density of 100 mA g?1 after 300 cycles and a superior discharge capacity of 915 mAh g?1 at 500 mA g?1 after 500 cycles. Even at a high current density of 1 and 2 A g?1, the core–shell structured C/SnO2 hollow spheres electrode still exhibits excellent discharge capacity in the long life cycles. Consideration of the superior performance and high yield, the core–shell structured C/SnO2 hollow spheres are of great interest for the next‐generation LIBs. 相似文献
2.
Yong Cheng Shaohua Wang Lin Zhou Limin Chang Wanqiang Liu Dongming Yin Zheng Yi Limin Wang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(26)
SnO2 has been considered as a promising anode material for lithium‐ion batteries (LIBs) and sodium ion batteries (SIBs), but challenging as well for the low‐reversible conversion reaction and coulombic efficiency. To address these issues, herein, SnO2 quantum dots (≈5 nm) embedded in porous N‐doped carbon matrix (SnO2/NC) are developed via a hydrothermal step combined with a self‐polymerization process at room temperature. The ultrasmall size in quantum dots can greatly shorten the ion diffusion distance and lower the internal strain, improving the conversion reaction efficiency and coulombic efficiency. The rich mesopores/micropores and highly conductive N‐doped carbon matrix can further enhance the overall conductivity and buffer effect of the composite. As a result, the optimized SnO2/NC‐2 composite for LIBs exhibits a high coulombic efficiency of 72.9%, a high discharge capacity of 1255.2 mAh g?1 at 0.1 A g?1 after 100 cycles and a long life‐span with a capacity of 753 mAh g?1 after 1500 cycles at 1 A g?1. The SnO2/NC‐2 composite also displays excellent performance for SIBs, delivering a superior discharge capacity of 212.6 mAh g?1 at 1 A g?1 after 3000 cycles. These excellent results can be of visible significance for the size effect of the uniform quantum dots. 相似文献
3.
Porous Carbon Nanofibers Encapsulated with Peapod‐Like Hematite Nanoparticles for High‐Rate and Long‐Life Battery Anodes 下载免费PDF全文
Fe2O3 is regarded as a promising anode material for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) due to its high specific capacity. The large volume change during discharge and charge processes, however, induces significant cracking of the Fe2O3 anodes, leading to rapid fading of the capacity. Herein, a novel peapod‐like nanostructured material, consisting of Fe2O3 nanoparticles homogeneously encapsulated in the hollow interior of N‐doped porous carbon nanofibers, as a high‐performance anode material is reported. The distinctive structure not only provides enough voids to accommodate the volume expansion of the pea‐like Fe2O3 nanoparticles but also offers a continuous conducting framework for electron transport and accessible nanoporous channels for fast diffusion and transport of Li/Na‐ions. As a consequence, this peapod‐like structure exhibits a stable discharge capacity of 1434 mAh g?1 (at 100 mA g?1) and 806 mAh g?1 (at 200 mA g?1) over 100 cycles as anode materials for LIBs and SIBs, respectively. More importantly, a stable capacity of 958 mAh g?1 after 1000 cycles and 396 mAh g?1 after 1500 cycles can be achieved for LIBs and SIBs, respectively, at a large current density of 2000 mA g?1. This study provides a promising strategy for developing long‐cycle‐life LIBs and SIBs. 相似文献
4.
Li Li Zhengjun Xie Gaoxue Jiang Yijing Wang Bingqiang Cao Changzhou Yuan 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(32)
Recently, binary ZnCo2O4 has drawn enormous attention for lithium‐ion batteries (LIBs) as attractive anode owing to its large theoretical capacity and good environmental benignity. However, the modest electrical conductivity and serious volumetric effect/particle agglomeration over cycling hinder its extensive applications. To address the concerns, herein, a rapid laser‐irradiation methodology is firstly devised toward efficient synthesis of oxygen‐vacancy abundant nano‐ZnCo2O4/porous reduced graphene oxide (rGO) hybrids as anodes for LIBs. The synergistic contributions from nano‐dimensional ZnCo2O4 with rich oxygen vacancies and flexible rGO guarantee abundant active sites, fast electron/ion transport, and robust structural stability, and inhibit the agglomeration of nanoscale ZnCo2O4, favoring for superb electrochemical lithium‐storage performance. More encouragingly, the optimal L‐ZCO@rGO‐30 anode exhibits a large reversible capacity of ≈1053 mAh g?1 at 0.05 A g?1, excellent cycling stability (≈746 mAh g?1 at 1.0 A g?1 after 250 cycles), and preeminent rate capability (≈686 mAh g?1 at 3.2 A g?1). Further kinetic analysis corroborates that the capacitive‐controlled process dominates the involved electrochemical reactions of hybrid anodes. More significantly, this rational design holds the promise of being extended for smart fabrication of other oxygen‐vacancy abundant metal oxide/porous rGO hybrids toward advanced LIBs and beyond. 相似文献
5.
Formation of N‐Doped Carbon‐Coated ZnO/ZnCo2O4/CuCo2O4 Derived from a Polymetallic Metal–Organic Framework: Toward High‐Rate and Long‐Cycle‐Life Lithium Storage 下载免费PDF全文
Ji‐Liang Niu Cheng‐Hui Zeng Hai‐Jun Peng Xiao‐Ming Lin Palanivel Sathishkumar Yue‐Peng Cai 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(47)
Metal–organic frameworks (MOFs) are very promising self‐sacrificing templates for the large‐scale fabrication of new functional materials owing to their versatile functionalities and tunable porosities. Most conventional metal oxide electrodes derived from MOFs are limited by the low abundance of incorporated metal elements. This study reports a new strategy for the synthesis of multicomponent active metal oxides by the pyrolysis of polymetallic MOF precursors. A hollow N‐doped carbon‐coated ZnO/ZnCo2O4/CuCo2O4 nanohybrid is prepared by the thermal annealing of a polymetallic MOF with ammonium bicarbonate as a pore‐forming agent. This is the first report on the rational design and preparation of a hybrid composed of three active metal oxide components originating from MOF precursors. Interestingly, as a lithium‐ion battery anode, the developed electrode delivers a reversible capacity of 1742 mAh g?1 after 500 cycles at a current density of 0.3 mA g?1. Furthermore, the material shows large storage capacities (1009 and 667 mAh g?1), even at high current flow (3 and 10 A g?1). The remarkable high‐rate capability and outstanding long‐life cycling stability of the multidoped metal oxide benefits from the carbon‐coated integrated nanostructure with a hollow interior and the three active metal oxide components. 相似文献
6.
Chaofan Yang Chong Qiao Yang Chen Xueqi Zhao Lulu Wu Yong Li Yu Jia Songyou Wang Xiaoli Cui 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(10)
High energy density is the major demand for next‐generation rechargeable batteries, while the intrinsic low alkali metal adsorption of traditional carbon–based electrode remains the main challenge. Here, the mechanochemical route is proposed to prepare nitrogen doped γ‐graphyne (NGY) and its high capacity is demonstrated in lithium (LIBs)/sodium (SIBs) ion batteries. The sample delivers large reversible Li (1037 mAh g?1) and Na (570.4 mAh g?1) storage capacities at 100 mA g?1 and presents excellent rate capabilities (526 mAh g?1 for LIBs and 180.2 mAh g?1 for SIBs) at 5 A g?1. The superior Li/Na storage mechanisms of NGY are revealed by its 2D morphology evolution, quantitative kinetics, and theoretical calculations. The effects on the diffusion barriers (Eb) and adsorption energies (Ead) of Li/Na atoms in NGY are also studied and imine‐N is demonstrated to be the ideal doping format to enhance the Li/Na storage performance. Besides, the Li/Na adsorption routes in NGY are optimized according to the experimental and the first‐principles calculation results. This work provides a facile way to fabricate high capacity electrodes in LIBs/SIBs, which is also instructive for the design of other heteroatomic doped electrodes. 相似文献
7.
A Robust and Conductive Black Tin Oxide Nanostructure Makes Efficient Lithium‐Ion Batteries Possible 下载免费PDF全文
Wujie Dong Jijian Xu Chao Wang Yue Lu Xiangye Liu Xin Wang Xiaotao Yuan Zhe Wang Tianquan Lin Manling Sui I‐Wei Chen Fuqiang Huang 《Advanced materials (Deerfield Beach, Fla.)》2017,29(24)
SnO2‐based lithium‐ion batteries have low cost and high energy density, but their capacity fades rapidly during lithiation/delithiation due to phase aggregation and cracking. These problems can be mitigated by using highly conducting black SnO2?x , which homogenizes the redox reactions and stabilizes fine, fracture‐resistant Sn precipitates in the Li2O matrix. Such fine Sn precipitates and their ample contact with Li2O proliferate the reversible Sn → Li x Sn → Sn → SnO2/SnO2?x cycle during charging/discharging. SnO2?x electrode has a reversible capacity of 1340 mAh g?1 and retains 590 mAh g?1 after 100 cycles. The addition of highly conductive, well‐dispersed reduced graphene oxide further stabilizes and improves its performance, allowing 950 mAh g?1 remaining after 100 cycles at 0.2 A g?1 with 700 mAh g?1 at 2.0 A g?1. Conductivity‐directed microstructure development may offer a new approach to form advanced electrodes. 相似文献
8.
Chaofan Yang Yong Li Yang Chen Qiaodan Li Lulu Wu Xiaoli Cui 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(8)
γ‐Graphyne is a new nanostructured carbon material with large theoretical Li+ storage due to its unique large conjugate rings, which makes it a potential anode for high‐capacity lithium‐ion batteries (LIBs). In this work, γ‐graphyne‐based high‐capacity LIBs are demonstrated experimentally. γ‐Graphyne is synthesized through mechanochemical and calcination processes by using CaC2 and C6Br6. Brunauer–Emmett–Teller, atomic force microscopy, X‐ray photoelectron spectroscopy, solid‐state 13C NMR and Raman spectra are conducted to confirm its morphology and chemical structure. The sample presents 2D mesoporous structure and is exactly composed of sp and sp2‐hybridized carbon atoms as the γ‐graphyne structure. The electrode shows high Li+ storage (1104.5 mAh g?1 at 100 mA g?1) and rate capability (435.1 mAh g?1 at 5 A g?1). The capacity retention can be up to 948.6 (200 mA g?1 for 350 cycles) and 730.4 mAh g?1 (1 A g?1 for 600 cycles), respectively. These excellent electrochemical performances are ascribed to the mesoporous architecture, large conjugate rings, enlarged interplanar distance, and high structural integrity for fast Li+ diffusion and improved cycling stability in γ‐graphyne. This work provides an environmentally benign and cost‐effective mechanochemical method to synthesize γ‐graphyne and demonstrates its superior Li+ storage experimentally. 相似文献
9.
Yaru Liang Xiang Xiong Zhuijun Xu Qingbing Xia Liyang Wan Rutie Liu Guoxin Chen Shu‐Lei Chou 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(26)
Lithium‐ion batteries (LIBs) have been widely applied and studied as an effective energy supplement for a variety of electronic devices. Titanium dioxide (TiO2), with a high theoretical capacity (335 mAh g?1) and low volume expansion ratio upon lithiation, has been considered as one of the most promising anode materials for LIBs. However, the application of TiO2 is hindered by its low electrical conductivity and slow ionic diffusion rate. Herein, a 2D ultrathin mesoporous TiO2/reduced graphene (rGO) heterostructure is fabricated via a layer‐by‐layer assembly process. The synergistic effect of ultrathin mesoporous TiO2 and the rGO nanosheets significantly enhances the ionic diffusion and electron conductivity of the composite. The introduced 2D mesoporous heterostructure delivers a significantly improved capacity of 350 mAh g?1 at a current density of 200 mA g?1 and excellent cycling stability, with a capacity of 245 mAh g?1 maintained over 1000 cycles at a high current density of 1 A g?1. The in situ transmission electron microscopy analysis indicates that the volume of the as‐prepared 2D heterostructures changes slightly upon the insertion and extraction of Li+, thus contributing to the enhanced long‐cycle performance. 相似文献
10.
Jin Bai Bangchuan Zhao Jiafeng Zhou Jianguo Si Zhitang Fang Kunzhen Li Hongyang Ma Jianming Dai Xuebin Zhu Yuping Sun 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(14)
1T phase MoS2 possesses higher conductivity than the 2H phase, which is a key parameter of electrochemical performance for lithium ion batteries (LIBs). Herein, a 1T‐MoS2/C hybrid is successfully synthesized through facile hydrothermal method with a proper glucose additive. The synthesized hybrid material is composed of smaller and fewer‐layer 1T‐MoS2 nanosheets covered by thin carbon layers with an enlarged interlayer spacing of 0.94 nm. When it is used as an anode material for LIBs, the enlarged interlayer spacing facilitates rapid intercalating and deintercalating of lithium ions and accommodates volume change during cycling. The high intrinsic conductivity of 1T‐MoS2 also contributes to a faster transfer of lithium ions and electrons. Moreover, much smaller and fewer‐layer nanosheets can shorten the diffusion path of lithium ions and accelerate reaction kinetics, leading to an improved electrochemical performance. It delivers a high initial capacity of 920.6 mAh g?1 at 1 A g?1 and the capacity can maintain 870 mAh g?1 even after 300 cycles, showing a superior cycling stability. The electrode presents a high rate performance as well with a reversible capacity of 600 mAh g?1 at 10 A g?1. These results show that the 1T‐MoS2/C hybrid shows potential for use in high‐performance lithium‐ion batteries. 相似文献
11.
Hierarchical TiO2/SnO2 Hollow Spheres Coated with Graphitized Carbon for High‐Performance Electrochemical Li‐Ion Storage 下载免费PDF全文
A self‐templated strategy is developed to fabricate hierarchical TiO2/SnO2 hollow spheres coated with graphitized carbon (HTSO/GC‐HSs) by combined sol–gel processes with hydrothermal treatment and calcination. The as‐prepared mesoporous HTSO/GC‐HSs present an approximate yolk‐double–shell structure, with high specific area and small nanocrystals of TiO2 and SnO2, and thus exhibit superior electrochemical reactivity and stability when used as anode materials for Li‐ion batteries. A high reversible specific capacity of about 310 mAh g?1 at a high current density of 5 A g?1 can be achieved over 500 cycles indicating very good cycle stability and rate performance. 相似文献
12.
Ping Wang Mengqi Shen Hu Zhou Chunfeng Meng Aihua Yuan 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(47)
The CuS(x wt%)@Cu‐BTC (BTC = 1,3,5‐benzenetricarboxylate; x = 3, 10, 33, 58, 70, 99.9) materials are synthesized by a facile sulfidation reaction. The composites are composed of octahedral Cu3(BTC)2·(H2O)3 (Cu‐BTC) with a large specific surface area and CuS with a high conductivity. The as‐prepared CuS@Cu‐BTC products are first applied as the anodes of lithium‐ion batteries (LIBs). The synergistic effect between Cu‐BTC and CuS components can not only accommodate the volume change and stress relaxation of electrodes but also facilitate the fast transport of Li ions. Thus, it can greatly suppress the transformation process from Li2S to polysulfides by improving the reversibility of the conversion reaction. Benefiting from the unique structural features, the optimal CuS(70 wt%)@Cu‐BTC sample exhibits a remarkably improved electrochemical performance, showing an over‐theoretical capacity up to 1609 mAh g?1 after 200 cycles (100 mA g?1) with an excellent rate‐capability of ≈490 mAh g?1 at 1000 mA g?1. The outstanding LIB properties indicate that the CuS(70 wt%)@Cu‐BTC sample is a highly desirable electrode material candidate for high‐performance LIBs. 相似文献
13.
Sesi Li Xuebing Zhao Yuzhang Feng Liting Yang Xiaofeng Shi Pingdi Xu Jie Zhang Peng Wang Min Wang Renchao Che 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(27)
Ternary transition metal oxides (TMOs) are highly potential electrode materials for lithium ion batteries (LIBs) due to abundant defects and synergistic effects with various metal elements in a single structure. However, low electronic/ionic conductivity and severe volume change hamper their practical application for lithium storage. Herein, nanosheet‐assembled hollow single‐hole Ni–Co–Mn oxide (NHSNCM) spheres with oxygen vacancies can be obtained through a facile hydrothermal reaction, which makes both ends of each nanosheet exposed to sufficient free space for volume variation, electrolyte for extra active surface area, and dual ion diffusion paths compared with airtight hollow structures. Furthermore, oxygen vacancies could improve ion/electronic transport and ion insertion/extraction process of NHSNCM spheres. Thus, oxygen‐vacancy‐rich NHSNCM spheres embedded into a 3D porous carbon nanotube/graphene network as the anode film ensure efficient electrolyte infiltration into both the exterior and interior of porous and open spheres for a high utilization of the active material, showing an excellent electrochemical performance for LIBs (1595 mAh g?1 over 300 cycles at 2 A g?1, 441.6 mAh g?1 over 4000 cycles at 10 A g?1). Besides, this straightforward synthetic method opens an efficacious avenue for the construction of various nanosheet‐assembled hollow single‐hole TMO spheres for potential applications. 相似文献
14.
Facile Synthesis of Ultrasmall CoS2 Nanoparticles within Thin N‐Doped Porous Carbon Shell for High Performance Lithium‐Ion Batteries 下载免费PDF全文
Qingfei Wang Ruqiang Zou Wei Xia Jin Ma Bin Qiu Asif Mahmood Ruo Zhao Yangyuchen Yang Dingguo Xia Qiang Xu 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(21):2511-2517
Cobalt sulfide (CoS2) is considered one of the most promising alternative anode materials for high‐performance lithium‐ion batteries (LIBs) by virtue of its remarkable electrical conductivity, high theoretical capacity, and low cost. However, it suffers from a poor cycling stability and low rate capability because of its volume expansion and dissolution of the polysulfide intermediates in the organic electrolytes during the battery charge/discharge process. In this study, a novel porous carbon/CoS2 composite is prepared by using nano metal–organic framework (MOF) templates for high‐preformance LIBs. The as‐made ultrasmall CoS2 (15 nm) nanoparticles in N‐rich carbon exhibit promising lithium storage properties with negligible loss of capacity at high charge/discharge rate. At a current density of 100 mA g?1, a capacity of 560 mA h g?1 is maintained after 50 cycles. Even at a current density as high as 2500 mA g?1, a reversible capacity of 410 mA h g?1 is obtained. The excellent and highly stable battery performance should be attributed to the synergism of the ultrasmall CoS2 particles and the thin N‐rich porous carbon shells derieved from nanosized MOF precusors. 相似文献
15.
Pine‐Needle‐Like Cu–Co Skeleton Composited with Li4Ti5O12 Forming Core–Branch Arrays for High‐Rate Lithium Ion Storage 下载免费PDF全文
Cheng‐ao Zhou Xinhui Xia Yadong Wang Zhujun Yao Jianbo Wu Xiuli Wang Jiangping Tu 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(16)
High‐performance of lithium‐ion batteries (LIBs) rely largely on the scrupulous design of nanoarchitectures and smart hybridization of bespoke active materials. In this work, the pine‐needle‐like Cu–Co skeleton is reported to support highly active Li4Ti5O12 (LTO) forming Cu–Co/LTO core–branch arrays via a united hydrothermal‐atomic layer deposition (ALD) method. ALD‐formed LTO layer is uniformly anchored on the pine‐needle‐like heterostructured Cu–Co backbone, which consists of branched Co nanowires (diameters in 20 nm) and Cu nanowires (250–300 nm) core. The designed Cu–Co/LTO core–branch arrays show combined advantages of large porosity, high electrical conductivity, and good adhesion. Due to the unique positive features, the Cu–Co/LTO electrodes are demonstrated with enhanced electrochemical performance including excellent high‐rate capacity (155 mAh g?1 at 20 C) and noticeable long‐term cycles (144 mAh g?1 at 20 C after 3000 cycles). Additionally, the full cell assembled with activated carbon positive electrode and Cu–Co/LTO negative electrode exhibits high power/energy densities (41.6 Wh kg?1 at 7.5 kW kg?1). The design protocol combining binder‐free characteristics and array configuration opens a new door for construction of advanced electrodes for application in high‐rate electrochemical energy storage. 相似文献
16.
Shuang Yuan Weibin Chen Lina Zhang Zekun Liu Jiaqi Liu Tie Liu Guojian Li Qiang Wang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(50)
Mn2O3 is a promising anode material for lithium‐ion batteries (LIBs) because of its high theoretical capacity and low discharge potential. However, low electronic conductivity and capacity fading limits its practical application. In this work, Mn2O3 with 1D nanowire geometry is synthesized in neutral aqueous solutions by a facile and effective hydrothermal strategy for the first time, and then Mn2O3 nanoparticle and nitrogen‐doped reduced graphene oxide (N‐rGO) are composited with Mn2O3 nanowires (Mn2O3‐GNCs) to enhance its volume utilization and conductivity. When used as an anode material for LIBs, the Mn2O3‐GNCs exhibit high reversible capacity (1350 mAh g?1), stable cycling stability, and good rate capability. Surprisingly, the Mn2O3‐GNC electrodes can also show fast charging capability; even after 200 cycles (charge: 10 A g?1; discharge: 0.5 A g?1), its discharge capacity can also keep at ≈500 mAh g?1. In addition, the Mn2O3‐GNCs also have considerable full cell and supercapacitor performance. The excellent electrochemical performances can be ascribed to the N‐rGO network structure and 1D nanowire structure, which can ensure fast ion and electron transportation. 相似文献
17.
Manas Ranjan Panda Rashmi Gangwar Divyamahalakshmi Muthuraj Supriya Sau Dhanshree Pandey Arup Banerjee Aparna Chakrabarti Archna Sagdeo Matthew Weyland Mainak Majumder Qiaoliang Bao Sagar Mitra 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(38)
The major challenges faced by candidate electrode materials in lithium‐ion batteries (LIBs) include their low electronic and ionic conductivities. 2D van der Waals materials with good electronic conductivity and weak interlayer interaction have been intensively studied in the electrochemical processes involving ion migrations. In particular, molybdenum ditelluride (MoTe2) has emerged as a new material for energy storage applications. Though 2H‐MoTe2 with hexagonal semiconducting phase is expected to facilitate more efficient ion insertion/deinsertion than the monoclinic semi‐metallic phase, its application as an anode in LIB has been elusive. Here, 2H‐MoTe2, prepared by a solid‐state synthesis route, has been employed as an efficient anode with remarkable Li+ storage capacity. The as‐prepared 2H‐MoTe2 electrodes exhibit an initial specific capacity of 432 mAh g?1 and retain a high reversible specific capacity of 291 mAh g?1 after 260 cycles at 1.0 A g?1. Further, a full‐cell prototype is demonstrated by using 2H‐MoTe2 anode with lithium cobalt oxide cathode, showing a high energy density of 454 Wh kg?1 (based on the MoTe2 mass) and capacity retention of 80% over 100 cycles. Synchrotron‐based in situ X‐ray absorption near‐edge structures have revealed the unique lithium reaction pathway and storage mechanism, which is supported by density functional theory based calculations. 相似文献
18.
Jiaxin Li Zebiao Li Weijian Huang Lan Chen Fucong Lv Mingzhong Zou Feng Qian Zhigao Huang Jian Lu Yangyang Li 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(18)
For Si anode materials used for lithium ion batteries (LIBs), developing an effective solution to overcome their drawbacks of large volume change and poor electronic conductivity is highly desirable. Here, the composites of ZnO‐incorporated and carbon‐coated silicon/porous‐carbon nanofibers (ZnO‐Si@C‐PCNFs) are designed and synthesized via a traditional electrospinning method. The prepared ZnO‐Si@C‐PCNFs can obviously overcome these two drawbacks and provide excellent LIB performance with excellent rate capability and stable long cycling life of 1000 cycles with reversible capacity of 1050 mA h g?1 at 800 mA g?1. Meanwhile, anodes of ZnO‐Si@C‐PCNFs attached with Ag particles display enhanced LIB performance, maintaining an average capacity of 920 mA h g?1 at a large current of 1800 mA g?1 even for 1000 cycles with negligible capacity loss and excellent reversibility. In addition, the assembling method with important practical significance for a simple pouch full cell is designed and used to evaluate the active materials. The Ag/ZnO‐Si@C‐PCNFs are prelithiated and assembled in full cells using LiNi0.5Co0.2Mn0.3O2(NCM523) as cathodes, exhibiting higher energy density (230 W h kg?1) of 18% than that of 195 W h kg?1 for commercial graphite//NCM523 full pouch cells. Importantly, the comprehensive mechanisms of enhanced electrochemical kinetics originating from ZnO‐incorporation and Ag‐attachment are revealed in detail. 相似文献
19.
Xi Zhao Hai Xu Zengyu Hui Yue Sun Chenyang Yu Jialu Xue Ruicong Zhou Lumin Wang Henghan Dai Yue Zhao Jian Yang Jinyuan Zhou Qiang Chen Gengzhi Sun Wei Huang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(47)
As an essential member of 2D materials, MXene (e.g., Ti3C2Tx) is highly preferred for energy storage owing to a high surface‐to‐volume ratio, shortened ion diffusion pathway, superior electronic conductivity, and neglectable volume change, which are beneficial for electrochemical kinetics. However, the low theoretical capacitance and restacking issues of MXene severely limit its practical application in lithium‐ion batteries (LIBs). Herein, a facile and controllable method is developed to engineer 2D nanosheets of negatively charged MXene and positively charged layered double hydroxides derived from ZIF‐67 polyhedrons into 3D hollow frameworks via electrostatic self‐assembling. After thermal annealing, transition metal oxides (TMOs)@MXene (CoO/Co2Mo3O8@MXene) hollow frameworks are obtained and used as anode materials for LIBs. CoO/Co2Mo3O8 nanosheets prevent MXene from aggregation and contribute remarkable lithium storage capacity, while MXene nanosheets provide a 3D conductive network and mechanical robustness to facilitate rapid charge transfer at the interface, and accommodate the volume expansion of the internal CoO/Co2Mo3O8. Such hollow frameworks present a high reversible capacity of 947.4 mAh g?1 at 0.1 A g?1, an impressive rate behavior with 435.8 mAh g?1 retained at 5 A g?1, and good stability over 1200 cycles (545 mAh g?1 at 2 A g?1). 相似文献
20.
Dong Cai Mengjie Lu La Li Junming Cao Duo Chen Haoran Tu Junzhi Li Wei Han 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(44)
Lithium–sulfur (Li–S) batteries have been considered as one of the most promising energy storage systems owing to their high theoretical capacity and energy density. However, their commercial applications are obstructed by sluggish reaction kinetics and rapid capacity degradation mainly caused by polysulfide shuttling. Herein, the first attempt to utilize a highly conductive metal–organic framework (MOF) of Ni3(HITP)2 graphene analogue as the sulfur host material to trap and transform polysulfides for high‐performance Li–S batteries is made. Besides, the traditional conductive additive acetylene black is replaced by carbon nanotubes to construct matrix conduction networks for triggering the rate and cycling performance of the active cathode. As a result, the S@Ni3(HITP)2 with sulfur content of 65.5 wt% shows excellent sulfur utilization, rate performance, and cyclic durability. It delivers a high initial capacity of 1302.9 mAh g?1 and good capacity retention of 848.9 mAh g?1 after 100 cycles at 0.2 C. Highly reversible discharge capacities of 807.4 and 629.6 mAh g?1 are obtained at 0.5 and 1 C for 150 and 300 cycles, respectively. Such kinds of pristine MOFs with high conductivity and abundant polar sites reveal broad promising prospect for application in the field of high‐performance Li–S batteries. 相似文献