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As low-cost commercial materials, the application of carbon nanotubes (CNTs) in the aluminum battery is limited by the lack of active intercalation sites. Herein, a flexible unzipped multi-walled carbon nanotubes (UCNTs) film consisting of graphene nanoribbons and a carbon nanotube backbone is prepared via a simple, low-cost and scalable method for high-performance aluminum battery positive electrode. In the nanostructure, the neonatal graphene nanoribbons provide numerous active intercalation sites to store AlCl4− anions, while the internal core CNTs are responsible for the rapid transportation of electrons to the active sites. Fast transportation of electrons and anions in UCNT film are simultaneously achieved, promoting the kinetics in the aluminum battery. Thus the UCNT-Al battery exhibits a high storage performance with a capacity as high as 100 mA h g−1 (current density: 2000 mA g−1) and a long cycle life of 5600 cycles with a capacity of 75 mA h g−1 (Coulombic efficiency: 98%) at 5000 mA g−1. Furthermore, the excellent flexibility and fast charging and variable discharging performance are beneficial for the development of portable devices. This work effectively tackles bottleneck caused by the lack of active sites for CNT-based aluminum batteries and accelerates the development of aluminum batteries.

Graphene is of great significance in energy storage devices. However, a graphene-based electrode is difficult to use in direct applications due to the large surface area and flexibility, which leads to the excessive consumption of electrolyte, low Coulombic efficiency, and electrode shedding behaviors. Herein, a special crystal carbon@graphene microsphere (CCGM) composite was successfully synthesized. The scalable carbonaceous microsphere composite displays a small specific surface area and a superior structure stability. As a potassium ion battery electrode in a half-cell, CCGM delivers an initial capacity of 297.89 mAh g

Structural modulation of catalytic nanostructures and fundamental understanding of their active sites at the atomic scale are important for predicting and improving the catalytic properties of nanostructures. Here, we prepared quasi-one-dimensional (1D) metal molybdenum (Mo) chains confined in atom-thick molybdenum disulfide (MoS2), referred henceforth as Mo/MoS2 nanosheets, and evaluated their hydrogen evolution reaction (HER) properties. The experiment and theoretical calculations show that the quasi-1D Mo chain with unsaturated coordination exhibits high HER activity. The unsaturated Mo sites in the chains increase the carrier density and facilitate the diffusion of hydrogen along the chains, mimicking an atomic scale reactor which leads to an experimentally observed enhanced catalytic performance. Within the framework of Volmer-Tafel model, the calculated kinetic barrier for H2 evolution is only 0.48 eV for Mo/MoS2, which is significantly lower than that for the Pt (111) surface (∼0.8 eV). In particular, Mo/MoS2 nanosheets supported on reduced graphene oxide (Mo/MoS2/RGO) outperformed commercial Pt on glassy carbon (Pt/C) in the practically meaningful high-current region (>140 mA cm−2) in 0.5 M H2SO4 solution and (15 mA cm−2) in 1.0 M NaOH solution, demonstrating that the Mo/MoS2/RGO could potentially replace Pt catalysts in practical HER systems. Additionally, this study provides crucial insights into the role of active centers in catalysis through a model-structure-performance relationship, thus pointing the way to a commercially viable technology for HER.

Lithium sulfur (Li-S) batteries are attracting increasing interest for high-density energy storage. However, the practical application is limited by the rapid capacity fading over repeated charge/discharge cycles which is largely attributed to the formation and shuttling of soluble polysulfide species. To address these issues, we develop a hierarchical structure composite with triple protection strategy via graphene, organic conductor PEDOT, and nitrogen and phosphorus codoped biological carbon to encapsulate sulfur species (GOC@NPBCS). This unique hierarchical structure can effectively immobilize the sulfur species while at the same time improve the electrical conductivity and ensure efficient lithium ion transport to enable excellent Li-S battery performance. In particular, the biological carbon derived from natural bacteria features inherent nitrogen and phosphorus codoping with a strong absorption to lithium polysulfides, which can greatly suppress the dissolution and shuttling of polysulfides that are responsible for rapid capacity fading. With these synergistic effects, the GOC@NPBCS cathode exhibits exceptionally stable cycling stability (an ultralow capacity fading rate of 0.045% per cycle during 1000 cycles at the current rate of 5 C), high specific capacity (1193.8 mAh g-1 at 0.5 C based on sulfur weight), and excellent rate capability.

With the development of society, rechargeable batteries are becoming ever-popular in people's lives. Although rechargeable sodium-ion batteries have attracted a large number of researchers, they suffer from the limited cycle stability and low capacity. To address these issues, tin-phosphorus-oxygen (SnPO) composite materials were protected by the curling of reduced graphene oxide (rGO) induced by the fluorine atoms from the electrolyte. The in-situ coating protection not only can increase the electrical conductivity, but also more importantly adjust the large volume expansion and suppress the pulverization of electrode materials during cycling. As a result, the SnPO composite delivers an initial discharge/charge capacity of 843 mAh g−1/450 mAh g−1at the current density of 50 mA g−1 and still retains a reversible discharge capacity of ∼420 mAh g−1 after 100 cycles. Moreover, it achieves a superior rate performance with the capacity of 200 mAh g−1at the current density of 2000 mA g−1. The superior electrochemical performance and the facile in-situ protection strategy will make a great contribution to the future development of rechargeable batteries.

We report an in situ alloying strategy for obtaining homogeneous (Bi,Sb) alloy nanoparticles from (Bi,Sb)2S3 nanotubes for the exceptional anode of potassium ion batteries (KIBs). The operando X-ray diffraction results, along with transmission electron microscopy and energy-dispersive X-ray spectroscopy mappings, successfully reveal the phase evolution of this material, which is (Bi,Sb)2S3 → (Bi,Sb) → K(Bi,Sb) → K3(Bi,Sb) during the initial discharge and K3(Bi,Sb) → K(Bi,Sb) → (Bi,Sb) in the charging process. The in situ alloying strategy produces a synergistic effect and brings an outstanding electrochemical performance. It achieves ultrahigh discharge capacities of 611 mAh g-1 at 100 mA g-1 (0.135C) and 300 mAh g-1 at 1000 mA g-1 (1.35C) and retains a capacity as high as 353 mAh g-1 after 1000 cycles at 500 mA g-1 (0.675C) with a Coulombic efficiency close to 100%. In addition, the KIBs full cell, which is composed of this anode and a perylenetetracarboxylic dianhydride cathode, reaches an initial discharge capacity as high as 276 mAh g-1 at 500 mA g-1 and maintains 207 mAh g-1 after 100 cycles.

To acquire remarkable cathode materials for lithium-sulfur batteries with ultrahigh utilization of active materials and superior cycling stability, we firstly employ carboxylated carbon nanotubes to prepare the NiCo2S4@CNTs/S for lithium-sulfur batteries via a simple hydrothermal method, following by a low temperature annealing. The NiCo2S4@CNTs presents a unique structure, which possesses thin branches filled with densely packed small leaves where a large number of micropores distribute. In the novel superstructure, carboxylated carbon nanotubes can effectively improve the electronic transportation capacity and conductivity of the cathode material. In lithium-sulfur batteries, bimetal sulfides have a strong adsorption of the polysulfides, effectively suppressing the diffusion of lithium polysulfides. The NiCo2S4@CNTs/S electrode shows a capacity of 788 mA h g−1 at the current density of 0.5 C and 758 mA h g−1 at 2 C. Even after 1000 cycles at the current density of 0.6 C the capacity only decays by 0.0489% each cycle. It should be notes that most of Coulombic efficiency of the NiCo2S4@CNTs/S electrode is about 99%, regardless of the current density. More importantly, the NiCo2S4@CNTs can exhibit an outstanding capability of absorbing lithium polysulfides, which provides a promising strategy for preparing advanced lithium-sulfur batteries.

Biomaterials play a significant role in energy storage devices owing to their renewable, inexpensive and eco-friendly peculiarity. In this study, potato biomass porous carbon (PBPC), which was fabricated by a facile two-step carbonization, was used as the anode material for potassium-ion batteries (KIBs). The crystal structure and mesoporous morphology of the carbon derivative at various carbonation temperatures are fully investigated. The electrochemical performance of PBPC electrodes is evaluated, presenting a high reversible specific capacity (248 mA h g−1 at 100 mA g−1), an excellent rate performance (152 mA h g−1 at 1000 mA g−1) and a superior cycle stability (almost no capacity decay after 400 cycles at a current density of 500 mA g−1 with a Coulombic efficiency about 100%). The superior electrochemical performance is mainly attributed to the uniformly distributed mesopores on PBPC electrode which facilitate the electrolyte transportation and diffusion. This work provides a simple and novel strategy to construct porous carbon as high-performance anode materials for KIBs through a sustainable and environment-friendly way.

Two-dimensional (2D) layered transition metal sulfide based materials are promising candidates for electrodes of lithium ion batteries (LIBs). As one of the representatives, molybdenum disulfide (MoS2), exhibits additional reversible capacity beyond their theoretical value although the lithium storage mechanism is still poorly understood. In this report, we developed a highly conducting metallic phase 1T(octahedral)-MoS2 based electrode with metal Mo atoms confined in “graphene nanoreactor” of abnormal lithium-storage sites, which delivered a high specific capacity of ~1800 mAh g−1 at 1 A g-1, about 2.6 times of its intercalation reactions value. Contrary to previous reports, a new lithium-storage mechanism for the high and ever-increasing capacity was proposed. The theoretical calculations and experiments show that a major contribution to the extra capacity in MoS2 anodes is due to Mo atoms accommodate with Li+. The Mo precipitates and their full contact with Li2S matrix enabled the reversible Mo→LixMo→Mo→1T-MoS2 reaction during charging/discharging processes. Over prolonged cycling, per Mo atomic could accommodate six Li+ ions. This new proposal could help to establish an accurate electrochemical reaction mechanism of MoS2 LIBs, which may lead to inspiration on new methods to greatly improve the performance of the MoS2 anode.

In this paper, the threshold voltage characteristics of silicon nanowire metal–oxide–semiconductor field-effect transistor (MOSFET) with a double-layer gate structure are presented. This type of device is considered to be the most promising application of nanodevice in ultralarge-scale integration, due to several advantages such as similar operation principle as the junctionless nanowire transistor, the screening effect of the upper gate (UG) to shield the lower gate MOSFETs from external electromagnetic disturbance, the tradeoff between the short channel and the thick-gate oxide layer, and the compatible fabrication process with the conventional MOS technology. In this paper, the relations of threshold voltage versus the gate length, the UG bias, the substrate bias, the drain bias, and the temperature are measured and analyzed. Moreover, the penetration effect of the UG electric field is proposed to interpret the short-channel characteristics of the device, and a piecewise curve model is presented to reveal the underlying physics of the relation of the threshold voltage versus the drain bias. The double-layer gate structure technology enables the design of many devices, such as small-signal analog circuit units, single-electron devices, and quantum bit cells.

Lithium–sulfur (Li–S) batteries have attracted great interest because of its high theoretical capacity (1675 mA h g–1). However, the low electrical conductivity of sulfur, dissolution of polysulfides, and structural collapse of electrode limit its practical application. Here an ultrathin honeycomb-like porous carbon derived from loofah sponge and doped with nitrogen (PCLSN) is prepared as a stable host for sulfur nanoparticles. Attributed to the integrated honeycomb structure, hierarchical porosity, ultrathin honeycomb walls, and synergistic effects between physical and chemical adsorption of polysulfides, the developed PCLSN@S cathode achieves a high initial specific capacity of 1379 mA h g–1 at 0.1 C, outstanding cyclability with a small capacity decay rate of 0.044% per cycle over 970 cycles at 2 C, excellent rate performance with a high capacity of 664 mA h g–1 at 3 C, and high sulfur content of PCLSN@S up to 76.1%. Our approach provides a promising route to design other 3D porous structures for high ...

Sodium ion battery attracts significant attentions due to its unlimited sodium resources and low cost. However, sodium ion battery usually suffers from the cathode materials' low capacity and poor cyclic stability. Here we demonstrate that the ultrafine Cu7S4 nanoparticles as cathode for sodium ion battery, which is in-situ generated during the cycling of commercial sulfur/graphene composite electrodes, can enable superior specific capacity and ultra-stable cycling performance. The Cu7S4 has an open crystal structure for Na+ insertion, the graphene conductive networks ensure the fast transportation of electrons and also provide more active sites, and the ultrafine-sized Cu7S4 with a larger specific surface area guarantees efficiently electrochemical reactions. Thus, the ultrafine Cu7S4 nanoparticles and graphene nanosheets composite exhibit a high capacity of 585.5 mAh g−1 (0.41 mAh cm−2) at the current density of 100 mA g−1, ultra-stable cycling performance even after 2000 cycles with a capacity of 409.9 mAh g−1 (0.29 mAh cm−2) at a current density of 500 mA g−1 and excellent rate performance even at the highest current density of 2000 mA g−1 with a reversible capacity of 277.1 mAh g−1 (0.19 mAh cm−2).

A highly stable Sb based anode material of well-confined Sb@graphene@carbon (Sb@G@C) was developed for high performance PIBs. The Sb@G@C electrode exhibits a reversible capacity of 474 mA h g-1 at 100 mA g-1 (second charge), an outstanding long cycle stability over 800 cycles with a capacity retention as high as 72.3% and an excellent rate performance.

The nanosized silicon for lithium-ion batteries (LIBs) is mainly limited by cracking and pulverization caused by the large volume change during deep cycles. Here, we demonstrated a commercial viability (scalable synthesis) of Si nanoparticles@graphene encapsulated in titanium dioxide nanotubes (Si@G@TiO2NTs) or carbon nanotubes (Si@G@CNTs) for the next generation of high-energy battery anodes. The nanotubes can not only provide strong protection and sufficient void space to buffer the huge volume expansion of Si nanoparticles during the charge/discharge process, but also enforce a most solid-electrolyte interphase to form on the outer surface of the nanotube instead of on individual Si nanoparticles, leading to ultrahigh coulombic efficiency and excellent cycling stability. The obtained Si@G@TiO2NT and Si@G@CNT electrodes showed a high reversible capacity of 1919.2 mA h g−1 (1.02 mA h cm−2) after 800 cycles and 2242.2 mA h g−1 (1.19 mA h cm−2) after 1000 cycles (>1 year) at the constant current density of 500 mA g−1, respectively. Furthermore, both Si@G@TiO2NT and Si@G@CNT electrodes presented superior average coulombic efficiency more than 99.9% during the whole cycling process.

Potassium‐ion batteries (KIBs) are one of the most appealing alternatives to lithium‐ion batteries, particularly attractive in large‐scale energy storage devices considering the more sufficient and lower cost supply of potassium resources in comparison with lithium. To achieve more competitive KIBs, it is necessary to search for anode materials with a high performance. Herein, the bimetallic oxide Sb2MoO6, with the presence of reduced graphene oxide, is reported as a high‐performance anode material for KIBs in this study, achieving discharge capacities as high as 402 mAh g−1 at 100 mA g−1 and 381 mAh g−1 at 200 mA g−1, and reserving a capacity of 247 mAh g−1 after 100 cycles at a current density of 500 mA g−1. Meanwhile, the potassiation/depotassiation mechanism of this material is probed in‐depth through the electrochemical characterization, operando X‐ray diffraction, transmission electron microscope, and density functional theory calculation, successfully unraveling the nature of the high‐performance anode and the functions of Sb and Mo in Sb2MoO6. More importantly, the phase development and bond breaking sequence of Sb2MoO6 are successfully identified, which is meaningful for the fundamental study of metal‐oxide based electrode materials for KIBs.

Potassium-organic batteries have a great potential for applications in the grid-scale energy storage owing to their low cost and abundant resources, although they suffer from the inferior cycle stability, fast capacity decay, and low power density. A highly reversible phase transformation of the organic cathode during potassiation/depotassiation is the key factor for the capacity retention, as revealed here. Consequently, the potassium-organic battery achieves a high power density of 9796 W kg-1 , a remarkable energy efficiency of 89%, a long cycle stability for 1000 cycles, a superior areal capacity around 2 mA h cm-2 , and a long-term cycling time over 8 months. Besides, the full cells also exhibit a superior rate performance and good cycle stability over 3000 cycles. This work provides new insight into the stabilization of the organic cathode, and demonstrates the enormous potential of organic cathodes for application in high-power potassium-ion batteries (PIBs), which may bring PIBs to new heights.

Lithium selenium batteries have received extensive attention for high volumetric energy density of 3254 mAh cm−3. However, the dissolution and volume change of selenium leads to rapid decay of capacity during the cycling process, which remains a challenge. Herein, we successfully synthesized the graphene encapsulated selenium/carboxylated carbon nanotubes (Se/CCNTs-RGO) composites by solvothermal strategy using 1-octadecene as the solvent. The CCNTs and RGO, which reduces volume expansion, enhances the rate of ion transport, and strongly limits the soluble polyselenides. The resulting Se/CCNTs-RGO exhibits outstanding electrochemical performances. It can deliver initial discharge capacity of 592 mAh g−1 at density of 200 mA g−1 and show excellent rate capability. This preparation method can be extended to other electrode materials for battery systems.

Sodium dual-ion batteries (NDIBs) are attracting extensive attention recently because of their low cost and abundant sodium resources. However, the low capacity of the carbonaceous anode would reduce the energy density, and the formation of the solid-electrolyte interphase (SEI) in the anode during the initial cycles will lead to large amount consumption of Na+ in the electrolyte, which results in low Coulombic efficiency and inferior stability of the NDIBs. To address these issues, a phosphorus-doped soft carbon (P-SC) anode combined with a presodiation process is developed to enhance the performance of the NDIBs. The phosphorus atom doping could enhance the electric conductivity and further improve the sodium storage property. On the other hand, an SEI could preform in the anode during the presodiation process; thus the anode has no need to consume large amounts of Na+ to form the SEI during the cycling of the NDIBs. Consequently, the NDIBs with P-SC anode after the presodiation process exhibit high Cou...

Single-wafer rapid thermal processing (RTP) is widely used in semiconductor manufacturing. Achieving temperature uniformity on silicon wafer is a major challenge in RTP control. In this work, a lamp configuration including five concentric lamp zones is designed to obtain uniform temperature distribution on the wafer. An optics-based model is developed to determine the optimal lamp design parameters, and a uniformity criterion is proposed to evaluate the effective irradiance distribution of the tungsten&ndash, halogen lamps on the wafer. This method can be used to determine geometric parameters of the lamp array in order to achieve uniform temperature distribution on the wafer. A realistic simulation of a cold wall RTP system with five lamp rings and a 200-mm wafer is performed. The proposed model makes way for a simple method for determining the optimal lamp design parameters in RTP systems.

Charge storage characteristics of MOSFET memory structure based on GeSi/Si hetero-nanocrystals (HNCs) are investigated by numerical simulation and experimental measurement. Owing to the advantages of a compound potential well and a higher offset at the valence band, this kind of memory has well hole storage. It is expected to serve as a high-performance nonvolatile memory operating at room temperature. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The parasitic capacitance effect and its influence to the performance have been investigated in Bipolar Junction Metal-Oxide-Semiconductor Field-Effect Transistor (BJMOSFET). The frequency characteristic equivalent circuit and high frequency response model of BJMOSFET have been presented. The frequency characteristic of BJMOSFET is simulated using the multi-transient analytical method and PSPICE9 simulator. The conclusions that BJMOSFET owns less total capacitance, wider frequency band, better transient characteristic and better frequency responses are reached by comparing with the traditional MOSFET at the same structure parameters and bias conditions. BJMOSFET, as a novel promising high frequency device, would be desired to find application in future integrated circuit.

In order to alleviate the influence of fluctuation of experimental data from noise and errors of measurement systems, a differential smoothing technique has been introduced into the extraction of threshold voltage of MOSFETs (Metal–Oxide–Semiconductor Field-Effect Transistors). The results show that the transconductance versus the gate voltage ( g m – V g ) curves could be smoother when the smoothing rank grows. A criterion to seek the best optimal fitting curve, named as the mismatch rate, has been proposed to obtain the threshold voltage parameter stably and automatically. This technique will contribute to the analysis of the characteristics of MOSFET and the designation of the integrated circuits.