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Vertically-grown few-layer MoS2 nanosheets on hierarchical carbon nanocages for pseudocapacitive lithium storage with ultrahigh-rate capability and long-term recyclability
摘要： Molybdenum disulfide (MoS2) are intensively studied anode materials for lithium-ion batteries (LIBs) owing to the high theoretical capacity, but still confront the severe challenges of unsatisfied rate capability and cycle life to date. Herein, few-layer MoS2 nanosheets are vertically grown on the hierarchical carbon nanocages (hCNC) via a facile hydrothermal method, which introduce pseudocapacitive lithium storage owing to the highly-exposed MoS2 basal planes, enhanced conductivity and facilitated electrolyte access arising from the well hybridization with hCNC. As a result, the optimized MoS2/hCNC exhibits the reversible capacity of 1670 mAh g-1 at 0.1 A g-1 after 50 cycles, 621 mAh g-1 at 5.0 A g-1 after 500 cycles, and 196 mAh g-1 at 50 A g-1 after 2,500 cycles, staying at the top level of the MoS2-based anode materials. The specific power and specific energy can reach to 16.1 kW kg-1 electrode and 252.8 Wh kg-1 electrode after 3,000 cycles, respectively, showing the great potential in high-power and long-life LIBs. This finding suggests a promising strategy for exploring advanced anode materials with high reversible capacity, high-rate capability and long-term recyclability.
关键词： pseudocapacitive lithium storage,vertical few-layer MoS2,hierarchical carbon nanocages,long-term recyclability,ultrahigh-rate capability
更新于2025-09-23 15:23:52
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LiF based scintillation neutron detector at high counting rates
摘要： In this work we revisit the problem of the restricted count rate capability of thermal neutron detectors utilizing the ZnS scintillator. The effect of the long afterglow of the scintillator on the detector performance at high counting rates is studied. A count rate capability substantially above values currently regarded as feasible is demonstrated.
关键词： thermal neutron detector,SiPM,ZnS:6LiF scintillator,count rate capability
更新于2025-09-23 15:21:01
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Realization of GaN-based gain-guided blue laser diodes by helium ion implantation
摘要： Na4MnV(PO4)3 (denoted as NMVP) has drawn increasing attention owing to the three-dimensional framework and high theoretical capacity. Nevertheless, the inherent low electronic conductivity of NMVP impedes the scale-up commercial applications. In this work, the feasibility to achieve ultrahigh-rate capability and long lifespan by in situ embedding the intertwined carbon nanotube (CNT) matrix into the bulk of Na4MnV-(PO4)3@C composites through a facile wet-chemical approach is reported. The elaborately prepared Na4MnV(PO4)3@C@CNTs cathode delivers a discharge capacity of 109.9 mA h g?1 at C/5 with an impressive rate capability of 68.9 mA h g?1 at an ultrahigh current rate of 90 C as well as a fascinating cycling performance of 68.3% capacity retention at 40 C after 4000 cycles. The optimum design of the 3D well-interconnected NMVP permitting fast kinetics for transported Na+/e? is bene?cial to the excellent electrochemical performance, which is further studied by the galvanostatic intermittent impedance spectra measurements. The pseudocapacitance contributions are also investigated. The research demonstrates that the dual-nanocarbon synergistically modi?ed NMVP composite is expected to facilitate the commercialization of sodium-ion batteries.
关键词： Na4MnV(PO4)3,sodium-ion batteries,ultrahigh-rate capability,long lifespan,CNTs
更新于2025-09-11 14:15:04
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Selective surface treatment by means of IR-laser – a new approach to enhance the rate capability of cathodes electrodes for Li-ion batteries
摘要： To meet today's demands on lithium-ion batteries for battery electrical vehicles in terms of energy density, electrodes with a high active mass loading as well as a low porosity are strived for. However, such high energy electrodes exhibit a poor rate capability, mainly due to limited lithium-ion diffusion. In this work, we present a laser-based surface treatment of calendered cathodes to partially overcome this conflict of objectives. NCM-based electrodes with different porosities were superficially modified by using IR-laser radiation with pulse duration in the nanosecond-regime. By detailed microscopic analysis, we show that it is possible to selectively ablate the binder/additive-compound without impairing the active material particles. Thus, it is possible to open surface pores which were closed during calendering by the binder/additive-compound. As a result, laser treated highly densified cathodes show a significantly improved rate capability at C-rates > 2C compared to untreated reference samples. The most significant improvement of > 20 % of the rate capability is found at 5C for electrodes with lowest porosity of 20 %. The experimental findings suggest that an enhanced electrolyte access to the active mass and thus, a reduced lithium-ion transport resistance lead to the improved electrochemical characteristics. In addition to the short-term rate capability tests, preliminary investigations of the cyclic stability of electrodes modified in such a way were performed. The state-of-health after one hundred 1C charge/discharge-cycles was about 95 % for both, the laser treated and the pristine electrodes.
关键词： surface modification,NCM cathode,Li-ion batteries,laser treatment,rate capability
更新于2025-09-11 14:15:04