With the popularity of mobile health monitoring and genome sequencing techniques, the scale of biomedical and genomic data grow rapidly, with their privacy receiving more and more concerns. Encryption technique plays an important role in many aspects of security guarantee for these data. For mobile devices, encryption is even more important yet more challenging, as these devices are usually used in environments that may not be well protected and have rather limited computing resources. With heterogeneous multi-core processors becoming popular on mobile devices to satisfy different needs of applications, designing heterogeneous algorithms to harness all the available resources are tricky but have the potential to deliver high performance. In this research, we study how to design the heterogeneous version for AES algorithm, a representative encryption algorithm, on such processor to improve throughput and energy efficiency. To alleviate the overhead, we proposed a hybrid strategy to firstly find optimal workload allocations for cores of the processor in the offline stage and then dynamically adjust the balance in the online stage to match the running environment. We do a series of experiments on common genome data, with results showing 25-400% improvements in throughput, and 5.5-2800% improvements in energy efficiency.

Aluminum-ion batteries (AIBs) are gaining attention for large-scale energy storage due to their low cost and high theoretical capacity. However, the existing cathode materials frequently encounter rapid capacity degradation and sluggish reaction kinetics due to the strong interaction with high-charge Al3+, which limits the utilization of AIBs. Here, the Se-doping strategy is proposed to facilitate the active participation of anions in charge compensation and enhance the anionic redox process of amorphous anion-rich TiS4. A refined amount of Se doping effectively improves reaction kinetics for Al-storage and stabilizes the structure of the material, preventing polysulfide dissolution under high dealumination states. As a result, amorphous TiS3.5Se0.5 delivers unprecedented Al3+ storage performance, with a stable capacity of 210 mAh g-1 at 500 mA g-1 over 400 cycles. Through detailed characterization, we reveal that a-TiS3.5Se0.5 undergoes reversible Al3+ insertion, accompanied by anionic redox processes involving S22-and Sen-species, which lays the foundation for further development of anionic-redox-based cathodes for high-performance AIBs.

In view of the inadequate energy density of hybrid supercapacitors, developing high-performance heterojunction electrodes is a promising strategy to solve this problem. However, the precise design and synthesis of heterojunction structure remains a challenge. In this work, a stacked NiCoSe clusters decorated cross-shaped star-like MOF-derived NiCo2O4 heterojunction (MOF-NiCo2O4@NiCoSe) was well-defined designed. The abundant heterogeneous interfaces and unique structure provide a large reactive area and structural stability during charge and discharge, thus facilitating the electrochemical reaction kinetics and boosting the electrochemical properties of electrode. Impressively, the obtained MOF-NiCo2O4@NiCoSe exhibits an excellent specific capacitance of 1266 F g(-1) at 1 A g(-1), outstanding multiplicative performance (91.6 % at 10 A g(-1)) and favorable cycling stability. In addition, the assembled device equipped with MOF-NiCo2O4@NiCoSe cathode exhibits uplifting electrochemical features in terms of a maximum energy density of 52.0 Wh kg(-1) at a power density of 800.0 W kg(-1) along with a high capacitance retention after 10,000 cycles.

Lithium–carbon dioxide (Li–CO 2 ) batteries, with high energy density and CO 2 utilization, are considered a promising candidate for Mars exploration. However, they continue to face challenges such as limited cycle life and significant polarization caused by anode degradation, which is often overlooked and whose underlying mechanism remains unclear. This work revealed the anode failure mechanism, identifying a water-triggered degradation process, which depletes active lithium content, and developed an atmosphere-induced protective strategy. The degradation is triggered by trace water and sustained by the CO 2 component, which results in transforming active lithium into Li 2 CO 3 . Thus, a strategy was provided to respond to the water molecules brought by the semi-hermetic system and high charging voltage. The protective layer was in situ polymerized and can interact with water molecules, leading to further polymerization, thereby inhibiting side reactions, significantly extending the battery's lifespan. The Li–CO 2 batteries can achieve stable cycling exceeding 1000 h, more than twice the time compared to the unprotected case. This study revealed the fundamental mechanism of anode degradation in Li–CO 2 batteries, providing a theoretical basis for the development of subsequent anode protection strategies. Additionally, it offers a viable method for anode protection in Li–CO 2 batteries.

ABSTRACT Lithium–carbon dioxide (Li–CO2) batteries with high theoretical energy density are regarded as promising energy storage system toward carbon neutrality. However, bidirectional catalysts design for improving the sluggish CO2 reduction reaction (CO2RR)/CO2 evolution reaction (CO2ER) kinetics remains a huge challenge. In this work, an advanced catalyst with fast‐interfacial charge transfer was subtly synthesized through element segregation, which significantly improves the electrocatalytic activity for both CO2RR and CO2ER. Theoretical calculations and characterization analysis demonstrate local charge redistribution at the constructed interface, which leads to optimized binding affinity towards reactants and preferred Li2CO3 decomposition behavior, enabling excellent catalytic activity during CO2 redox. Benefiting from the enhanced charge transfer ability, the designed highly efficient catalyst with dual active centers and large exposed catalytic area can maintain an ultra‐small voltage gap of 0.33 V and high energy efficiency of 90.2%. This work provides an attractive strategy to construct robust catalysts by interface engineering, which could inspire further design of superior bidirectional catalysts for Li–CO2 batteries.

Phase change materials (PCMs) exhibit significant application potential as thermal management materials across various sectors, especially composite PCMs with mechanical flexibility and high latent heat. Despite recent advances in PCMs encapsulation technology, their applications are often severely limited by insufficient mechanical properties and complex manufacturing processes. Herein, a layered engineering strategy of a three-dimensional network structure was reported, achieving PEG encapsulation and a mechanically flexible support structure. Benefiting from the synergy of rigid cellulose nanofibers and flexible polyacrylamide hydrogel, the prepared phase change composites achieve a noteworthy level of flexibility and tensile strength (4.9 MPa), along with significantly high latent heat (138.5 J/g) and thermal cycle stability. These bendable and foldable flexible composites with phase transition properties are suitable for the thermal management of complex equipment particularly as a potential candidate material for environmental temperature regulation and thermal protection. Overall, this work proposes a novel strategy to combine hydrogel and biomass materials to prepare support frameworks for PCMs encapsulation, which will foster potential advances in flexible phase change composites.

Thin film microbattery is urgently needed to provide a long-term stable on-chip power for various kinds of microdevices or microsystems. Anode is a core component in thin film lithium ion microbattery, however, previous researches mostly focused on metal oxide or Si-based thin film anodes, and the reports of metal sulfide thin film anodes are limited. Herein, we present a new type of Ti-doped ZnS thin film fabricated by radio frequency (RF) magnetron co-sputtering. The Ti doping is designed to enhance the overall electrical conductivity of the ZnS thin film, since the insulation of ZnS is one of the major barriers to deliver its lithium storage performance. As an anode applied in lithium ion battery, the Ti-doped ZnS thin film exhibits good cycling stability up to 500 cycles at a current density of 1.0 A·g −1 , and remains a higher specific capacity of 463.1 mAh·g −1 than that of the pure ZnS thin film, showing its better electrochemical reaction reversibility. The rate capability and EIS measurements manifest the more favorable electrochemical reaction kinetics of the Ti-doped ZnS thin film, moreover, the CV tests at various scan rates indicate the improved Li + diffusion kinetics in the electrode after Ti doping.

To effectively boost the dielectric loss, herein, mixed-dimensional Ni foam (NF)/ZnCo2O4 @NiO conductive network heterostructures consisting of three-dimensional (3D) NF, one-dimensional (1D) ZnCo2O4 nanowires and two-dimensional (2D) NiO nanosheets were designed and produced by a simple two-step method. The growth of 1D ZnCo2O4 nanowires on the surface of 3D NF was done by a hydrothermal process, followed by the chemical bath deposition (CBD) of 2D NiO nanosheets. The obtained results indicated that the NiO content in the as-prepared NF/ZnCo2O4 @NiO network heterostructures could be promoted by increasing the CBD time, which improved their specific surface areas. Owing to utilizing the multiple interfaces for enhancing the interfacial polarization, the as-prepared NF/ZnCo2O4 @NiO network heterostructures presented the remarkably enhanced electromagnetic wave absorption performances (EMWAPs) compared to NF/ZnCo2O4 nanowire arrays. Moreover, the EMWAPs of mixed-dimensional NF/ZnCo2O4 @NiO network heterostructures could be further optimized by increasing the NiO content, which was demonstrated to promote the interfacial polarization. Generally, the findings demonstrated that taking full advantage of interface engineering in constructing the mixed-dimensional conductive network heterostructures is a very effective strategy to aggrandize dielectric loss, which provided an efficient and promising strategy to develop the novel and high-efficient microwave absorbers.

To enhance the utilization of active materials and transform the traditional electrode preparation technology, a binder-free ultrathin SnS2 anode for lithium ion batteries is fabricated through a simple magnetron sputtering method. In comparison with the electrode synthesized by solvothermal method and coating process, the binder-free SnS2 electrode presents superior reversibility of conversion reaction due to the shorter ions and electrons transport path and the close contact of the active material with the electrolyte, suggesting a restraining effect on the tin agglomeration, then stabilize the electrode structure, it retains the superior capacity retention of 80% after 200 cycles at 0.5 A g(-1) and the high rate capability of 788 mAh g(-1) at 5.0 A g(-1). The ultratiny SnS2 nanoparticles uniformly arrayed on the substrate and occurred dominant pseudocapacitive effect, guaranteeing its high-rate performance with 967 mAh g(-1) at 1.0 A g(-1) after 200 cycles. The stable electrode morphology after cycling demonstrates its prospect for lithium ion batteries anode. (C) 2021 Elsevier B.V. All rights reserved.

Metal sulfides are promising anode materials for lithium ion batteries because of the high specific capacities and better electrochemical kinetics comparing to their oxide counterparts. In this paper, novel monocrystalline wurtzite ZnS@N-doped carbon (ZnS@N–C) nanoplates, whose morphology and phase are different from the common ZnS particles with cubic phase, are successfully synthesized. The ZnS@N–C nanoplates exhibit long cycle life with a high reversible specific capacity of 536.8 mAh · g −1 after 500 cycles at a current density of 500 mA · g −1 , which is superior to the pure ZnS nanoplates, illustrating the obvious effect of the N-doped carbon coating for mitigating volume change of the ZnS nanoplates and enhancing the electronic conductivity during charge/discharge processes. Furthermore, it is revealed that the ZnS single crystals with wurtzite phase in the ZnS@N–C nanoplates are transformed to the polycrystalline cubic phase ZnS after charge/discharge processes. In particular, the ZnS@N–C nanoplates are combined with the commercial LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode to fabricate a new type of LiNi 0.6 Co 0.2 Mn 0.2 O 2 /ZnS@N–C complete battery, which exhibits good cycling durability up to 120 cycles at a charge/discharge rate of 1 C after the prelithiation treatment on the ZnS@N–C anode, highlighting the potential of the ZnS@N–C nanoplates anode material applied in lithium ion battery.

Thin-film lithium-ion microbatteries with a high energy density and long lifespan are exceedingly desired for developing self-powered integrated micro-nano devices and systems. However, exploring high-performance thin-film anodes still remains a challenge. Herein, a double-layer-structure diamond-like carbon-ZnS (DLC-ZnS) thin-film anode fabricated by radio frequency magnetron sputtering exhibits high specific capacity and good cycling stability up to 1000 cycles, superior to the pure ZnS thin-film anode. To understand the mechanism, the bimodal amplitude modulated-frequency modulated atomic force microscopy was used to explore the mechanical properties of the thin films, and the DLC layer shows significantly higher Young's modulus than the ZnS thin film. The DLC interface with a high Young's modulus can effectively buffer the mechanical stress originating from the huge volume changes of the ZnS layer during lithiation/delithiation processes; therefore, the DLC interface maintains the higher mechanical integrity of the DLC-ZnS thin film and improves the utilization of ZnS. In addition, the electrochemical kinetics of the DLC-ZnS and ZnS thin films were also investigated by electrochemical methods. Electrochemical impedance spectroscopy tests indicate the obstacle of the DLC interface to Li+ ion diffusion in the initial charge/discharge processes; however, the DLC-ZnS thin film exhibits lower total resistance than the ZnS thin film afterward. In particular, galvanostatic intermittent titration technique tests were performed to find out the differences between the two thin films during the galvanostatical charge/discharge processes. The results demonstrate the obviously enhanced conversion reaction reversibility and decreased alloy reaction polarization of the DLC-ZnS thin film; therefore, it delivers higher reversible capacity.

A facile generic solvothermal strategy is employed to prepare C/SnOx/MoOy composite with evenly distributed C, Sn, Mo and O elements. The multi-element characteristic of active components and the introduction of carbon phase contribute greatly to the improved electrochemical performance as LIBs anodes. The influence of carbon phase and content of Sn and Mo on electrochemical behavior were investigated in this work. Carbon phase contributes greatly to the enhanced electric conductivity, structural integrity and pseudocapacitance contribution of the electrode. The best electrochemical performance is achieved in carbon/Sn–Mo oxide anode with a Sn/Mo ratio of about 1:1, indicating the mutual buffering relationship between Sn and Mo due to the different working voltage toward lithium. As a result, an excellent capacity retention of 98% (vs 2nd cycle) is delivered after 500 cycles at 0.5 A g−1. Even at a high rate of 2.0 A g−1, the capacity could be well remained after 500 cycles. Moreover, full cell employing such a C/SnOx/MoOy anode in combination with LiCoO2 cathode offers a good cycling performance.

Polarization of lithium-sulfur (Li-S) batteries consumes energy density upon cycling, which precludes their practical application in state-of-the-art devices. Herein a conformal zinc sulfide/reduced graphene oxide/elemental sulfur (ZnS/rGO/S) composite is synthesized and used as cathode materials in Li-S batteries. The synergetic regulation of ohmic, concentration, and electrochemical polarization decreases the overpotential and improves the cycling performance of the Li||ZnS/rGO/S cell. Combining theoretical calculations and experimental results, it is revealed that the ZnS spheres can absorb lithium polysulfide (LPS) intermediates, catalyze LPS conversion, and provide fast electronic/ionic diffusion kinetics. The ZnS/rGO/S cathode is further applied in pouch Li-S cells, demonstrating the practicability of sulfur cathodes with reduced polarization.

Core-shell Fe3O4-polypyrrole (Fe3O4-PPy) composites are synthesized by etching and polymerization to address the capacity degradation and low Coulombic efficiency (CE) of the Fe3O4 electrodes for lithium storage. When the weight content of Fe3O4 is 60%, a conformal carbon-coated Fe3O4 composite is formed, which can retain a charge capacity of 451 mAh g(-1) after 800 cycles at 2 C with a high initial CE of 74.8%. The diffusive and capacitive contribution to the capacity are evulated, demonstating the advantages of the synergistic lithiation of the Fe3O4-PPy electrodes. (C) 2020 Published by Elsevier B.V.

以猕猴桃皮为碳源,通过水热法制备出了水溶性的荧光碳点,制备步骤简单、成本低廉.通过透射电镜(TEM)、X-射线粉末衍射(XRD)、红外光谱(FT-IR)、拉曼光谱(Raman)等手段对荧光碳点形貌和化学组成进行分析,并通过紫外可见吸收光谱(UV-Vis)和荧光发射光谱(PL)对其光学性能进行研究,还对其在荧光油墨方面的应用做了初步尝试.结果表明:所制备的荧光碳点在365 nm紫外灯照射下呈现蓝色荧光,并表现出激发波长依赖性,具有很好的稳定性和抗离子干扰能力;该荧光碳点用作绿色、低成本的荧光油墨,用其书写或印刷的图文在可见光下隐形,可用于记录、存储和加密信息.

Transition metal oxide (TMO) is an important type of conversion reaction anode for lithium ion batteries. Carbon encapsulated zinc oxide and cobalt oxide (ZnO@C, Co3O4@C) were prepared via a MOF-derived strategy. MOF precursors were firstly coated with polypyrrole (PPy) layer and then subjected to subsequent thermal treatment. Benefiting from the synergetic effect of conductive coating layer and 3D porous structure, both anodes showed attractive electrochemical performance. The ZnO@C and Co3O4@C delivered a reversible capacity of 526 and 721 mAh.g(-1) after 500 cycles at 250 mA g(-1). With attractive rate performance, the ZnO@C and Co3O4@C have an average capacity of 301 and 306 mAh.g(-1) at 2.0 A g(-1). Kinetic analysis revealed that lithium ion storage in both ZnO@C and Co3O4@C were dominated by a surface controlled pseudo-capacitive process. In addition, ZnO@C and Co3O4@C could even stably cycle for 1000 times at a high current density of 2.0 A g(-1). (C) 2019 Elsevier B.V. All rights reserved.

Pseudocapacitive P-doped nickel cobaltate (P-NCO) porous microspheres were prepared via a two-step strategy. The P-NCO showed superior electrochemical performance than the pristine NiCo2O4 as anode material for lithium ion batteries (LIBs). A reversible discharge capacity of 470mAh g(-1) can be maintained after 1000 cycles at a current density of 500 mA g(-1), with an average capacity loss rate of 0.015% per cycle. The P-doped anode could deliver a reversible capacity of 496, 417, 303 and 210 mAh g(-1) at 1.0, 2.0, 3.0 and 4.0 A g(-1). Kinetic analysis revealed that pseudocapacitance plays a vital role in the lithium ion storage, which endows the P-NCO higher rate capacities and cycling stability. Attractive performance of the P-NCO anode is ascribed to the synergetic effect of porous structure and P-doping modification. The P-NCO demonstrates as a promising alternative to conventional anodes. (C) 2018 Published by Elsevier B.V.

The low electrical conductivity and poor cycling stability at high current density of hausmannite (Mn3O4) have greatly limited its practical application in commercial lithium ion batteries (LIBs). In order to tackle these above issues, porous carbon encapsulated Mn3O4 has been designed and prepared. Carbon-encapsulated Mn3O4 (Mn3O4@C) prepared via a MOF-derived strategy shows attractive cycling stability and rate performance in both half-cells and full cells. It could stably deliver a capacity of 730.20 mAh g(-1) after 200 cycles at 250 mA g(-1). An average capacity of 421 mAh g(-1) is obtained at a current density of 4000 mA g(-1). After a 400-cycle test at 2000 mA g(-1), the Mn3O4@C anode can maintain 70.90% of its initial capacity. Full cells using Mn3O4@C as anode and NCM-523 as cathode could stably cycle for 100 times at 200 mA g(-1), with a 73.30% capacity retention. Conversion mechanism of the Mn3O4@C anode has been investigated by ex-situ XPS. Upon the first discharge, Mn3O4 is initially reduced into MnO and further reduced into metallic Mn-0. The metallic Mn-0 is then converted into MnO during the following charge. Subsequent lithiation/de-lithiation are governed by reversible conversion between MnO and metallic Mn-0. Improved electrochemical performance of the Mn3O4@C anode is attributed to introduction of porous carbon, which could not only limit loss of active species but also enhance overall electrical conductivity. The Mn3O4@C composite can be a promising anode material for LIBs. (C) 2019 Elsevier Ltd. All rights reserved.

Undoubtedly, silicon/carbon composites are one of the most promising anode classes for lithium-ion battery. However, they still suffer from poor cycle performance despite the introduction of carbon phase, which is usually expected to inhibit the volume expansion of Si phase and meanwhile enrich the electrode conductivity, improving the cycle stability. Here, a double-carbon protected silicon anode was designed and successfully synthesized through the liquid coating and in-situ polymerization method. In this structure, the primary seamless carbon layer make Si NPs maintain a close contact to conducting carbon, so that inserted Li+ could fully react with Si, improving the utilization of active materials. The secondary carbon skeleton could help to maintain the mechanical integrity of the structure and meanwhile enrich the charge transfer channels. The structural advantages enhance the mechanical integrity and electrochemical kinetics during cycling, that lead to superior electrochemical Li+ storage performance. The resulting double-carbon protected silicon anode demonstrates a high specific capacity, long-term stability (1919 mAh g(-1) at 0.5 mA g(-1), 90% retention after 400 cycles (vs. the capacity of second cycle)) and outstanding rate capability (1170 mAh g(-1) at 2 A g(-1)). (C) 2019 Elsevier B.V. All rights reserved.