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- Yang, Chaoran, et al.
(författare)
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Alternate-stacked Li4Ti5O12 nanosheets/d-Ti3C2 flexible film as a current collector-free, high-capacity and robust cathode for rechargeable Mg batteries
- 2020
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Ingår i: Nano select. - : John Wiley & Sons. - 2688-4011. ; 1:1, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Rechargeable magnesium batteries (RMBs) have gained increasing attention owing to its high volumetric capacity, crust abundance, and safety from dendrite-free characteristic. However, the lack of development of high-performance cathode materials with long cycling stability and satisfactory capacity has greatly restricted the development of RMBs. Herein, a self-supported, current collector-free and soft electrode is prepared with delaminated Ti3C2 (d-Ti3C2) and Li4Ti5O12 nanosheets by simple vacuum filtration as flexible cathode in RMBs. Fabricated into a full cell with hybrid AlCl3/MgCl2/Mg(TFSI)2 electrolyte and Mg anode (a thin Mg foil with thickness of 50 μm), the flexible cathode shows high initial specific capacity of 320 mAh g−1 at 20 mA g−1, excellent cycling stability (good retention even after 1000 cycles) and outstanding rate performance. Detailed mechanistic studies reveal that introduction of d-Ti3C2 provide fast transport paths for electrons and Mg2+. The enlarged layer spacing of composited d-Ti3C2 accounts for significant increment in capacity. Benefiting from above-mentioned advantages, the best performance among Ti-based electrode materials is realized and make wearable devices powered by RMBs possible, thus circumventing the safety issues of lithium batteries.
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- Yang, Jianming, et al.
(författare)
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Comprehensive understanding of heat-induced degradation of triple-cation mixed halide perovskite for a robust solar cell
- 2018
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Ingår i: Nano Energy. - : ELSEVIER SCIENCE BV. - 2211-2855 .- 2211-3282. ; 54, s. 218-226
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Tidskriftsartikel (refereegranskat)abstract
- The triple-cation mixed halide perovskite Cs-0.05(MA(0.17)FA(0.83))(0.95)Pb(I0.83Br0.17)(3) emerges as one of the most promising candidates for photovoltaics due to superior optoelectronic properties, but the thermal stability is still a major challenge for the viability of perovskite solar cells towards commercialization. Herein, we firstly explore the thermal response of the photovoltaic performances to access device physical changes. It is shown that the efficiency loss originates from decreased charge mobility, increased trap density and generation of PbI2 charge recombination centers near the interface. In-depth analysis of evolutions in morphology, chemical composition, dynamic and electronic structure of the perovskite layer at the nanometer scales indicates that it is initial dangling bonds and vacancies on the imperfect surfaces decrease the activation energy and cause the perovskite decomposition in a layer-by-layer pathway sequentially from the film surface to bulk. Based on the results, a strategy of surface passivation to improve the thermal stability is demonstrated and discussed. This work for the first time provides insights into the physical and chemical change of such triple-cation perovskite and indicates that more effort should be invested in surface treatment for enhancing perovskite device stability.
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