Silicon is emerging as a promising next-generation lithium-ion battery anode because of its high theoretical capacity and low cost.However,the poor cyclability and inferior rate performance hinder its largescale appli...Silicon is emerging as a promising next-generation lithium-ion battery anode because of its high theoretical capacity and low cost.However,the poor cyclability and inferior rate performance hinder its largescale applications.Here,hollow silicon/germanium(H-SiGe)nanospheres with a binary-active component and heterogeneous structure combined with porous carbon(pC)reinforcing are synthesized as lithium-ion battery anodes.Experimental studies demonstrate that the H-SiGe/pC anodes possess tiny volume expansion,high ion/electron conductivity,and stable electrode interface.Theoretical calculations confirm that through the replacement of Si using Ge with rational component control,the diffusion energy barrier of lithium will be reduced and lithium storage ability can be improved because of the slight charge polarization.Benefiting from these unique merits,the H-SiGe/pC anodes display a high initial specific capacity of 2922.2 mA h g^(-1)at 0.1 A g^(-1),superior rate capability(59.4%capacity retention from 0.5 to 8 A g^(-1)),and excellent cycling stability(81%retention after 700 cycles at 5 A g^(-1)at 1.0–1.2 mg cm^(-2)).An outstanding stability is preserved even at a high loading of 3.2 mg cm^(-2)with an improved reversible capacity of 429.1 mA h g^(-1)after 500 cycles at 4 A g^(-1).Furthermore,the full-cell with the prelithiated H-SiGe/pC anode and LiFePO4cathode exhibits an impressive capacity performance.展开更多
<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i&l...<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">nanosheets</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> prepared by means of ultrasound-assisted liquid </span><span style="font-family:Verdana;font-size:12px;">phase exfoliation (LPE)</span><span style="font-family:Verdana;font-size:12px;"> and the </span><span style="font-family:Verdana;font-size:12px;">nonlinear </span><span style="font-family:Verdana;font-size:12px;">saturable absorption</span><span style="font-family:Verdana;font-size:12px;"> properties</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were experimentally</span><span style="font-family:Verdana;font-size:12px;"> investigated. The modulation depth, saturation intensity and nonsaturable absorbance</span><span style="font-family:Verdana;font-size:12px;"> of the prepared </span><span style="font-family:Verdana;font-size:12px;">1T-TiSe</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">SA </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">1</span><span style="font-family:Verdana;font-size:12px;">5.7</span><span style="font-family:Verdana;font-size:12px;">%,</span><span style="font-family:Verdana;font-size:12px;"> 1.28 M</span><span style="font-family:Verdana;font-size:12px;">W/cm</span><sup><span style="font-family:Verdana;font-size:12px;vertical-align:super;">2</span></sup><span style="font-family:Verdana;font-size:12px;"> and 8.</span><span style="font-family:Verdana;font-size:12px;">2</span><span style="font-family:Verdana;font-size:12px;">%, </span><span style="font-family:Verdana;font-size:12px;">respectively</span><span style="font-family:Verdana;font-size:12px;">. Taking advantage of the saturable absorption properties of </span><span style="font-family:Verdana;font-size:12px;">T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;">-based SA, a passively Q-switched erbium-doped fiber (EDF) laser was</span><span style="font-family:Verdana;font-size:12px;"> systematically demonstrated</span><span style="font-family:Verdana;font-size:12px;">. The pulse repetition rates varied from 24.50 kHz up to 73.79 kHz with the increasing pump power. The obtained shortest pulse width was 1.31 </span><span style="font-family:Verdana;font-size:12px;">μ</span><span style="font-family:Verdana;font-size:12px;">s with pulse energy of 79.28 nJ. The </span><span style="font-family:Verdana;font-size:12px;">system presented merits of low-cost SA preparation, system compactness,</span><span style="font-family:Verdana;font-size:12px;"> superb stability and high competition.</span>展开更多
Niobium telluride(NbTe_(2)),an emerging transition metal dichalcogenide material,has been theoretically predicted to have nonlinear absorption properties and excellent optical response.However,only a few studies of th...Niobium telluride(NbTe_(2)),an emerging transition metal dichalcogenide material,has been theoretically predicted to have nonlinear absorption properties and excellent optical response.However,only a few studies of the utilization of NbTe_(2)in ultrafast photonics have been reported.In this work,a NbTe_(2)-based saturable absorber(SA)was applied in an erbium-doped fiber as a mode-locked device,and a vector soliton based on NbTe_(2)was obtained for the first time.NbTe_(2)-PVA film SA was successfully prepared by the liquid-phase exfoliation and spin coating methods,with a modulation depth of up to 10.87%.The nonlinear absorption coefficient of NbTe_(2)-based SA film tested through the open-aperture Z-scan laser measurement is 0.62×10^(−11) m/W.A conventional soliton with a pulse duration of 858 fs was generated using NbTe_(2)-based SA,which was demonstrated to be a kind of polarization-locked vector soliton in further investigation.Our experimental results reveal the nonlinear optical properties of NbTe_(2)and broaden its applications in ultrafast photonic devices.展开更多
As a member of Xenes family,germanene has excellent nonlinear saturable absorption characteristics.In this work,we prepared germanene nanosheets by liquid phase exfoliation and measured their saturation intensity as 0...As a member of Xenes family,germanene has excellent nonlinear saturable absorption characteristics.In this work,we prepared germanene nanosheets by liquid phase exfoliation and measured their saturation intensity as 0.6 GW/cm^(2) with a modulation depth of 8%.Then,conventional solitons with a pulse width of 946 fs and high-energy noise-like pulses with a pulse width of 784 fs were obtained by using germanene nanosheet as a saturable absorber for a mode-locked Erbium-doped fber laser.The characteristics of the two types of pulses were investigated experimentally.The results reveal that germanene has great potential for modulation devices in ultrafast lasers and can be used as a material for creation of excellent nonlinear optical devices to explore richer applications in ultrafast photonics.展开更多
In this study,titanium disulfide(TiS_(2))polyvinyl alcohol(PVA)film-type saturable absorber(SA)is synthesized with a modulation depth of 5.08%and a saturable intensity of 10.62 MW/cm^(2) by liquid-phase exfoliation an...In this study,titanium disulfide(TiS_(2))polyvinyl alcohol(PVA)film-type saturable absorber(SA)is synthesized with a modulation depth of 5.08%and a saturable intensity of 10.62 MW/cm^(2) by liquid-phase exfoliation and spin-coating methods.Since TiS2-based SA has a strong nonlinear saturable absorption property,two types of optical soliton were observed in a mode-locked Er-doped fiber laser.When the pump power was raised to 67.3 mW,a conventional mode-locked pulse train with a repetition rate of 1.716 MHz and a pulse width of 6.57 ps was generated,and the output spectrum centered at 1556.98 nm and 0.466 nm spectral width with obvious Kelly sidebands was obtained.Another type of mode-locked pulse train with the maximum output power of 3.92 mW and pulse energy of 2.28 nJ at the pump power of 517.2 mW was achieved when the polarization controllers were adjusted.Since TiS2-based SA has excellent nonlinear saturable absorption characteristics,broad applications in ultrafast photonic are expected.展开更多
Indium selenide(InSe)is a typical layered metal-chalcogenide semiconductor that has potential for developing ultrafast optoelectronic devices.In this work,InSe-polyvinyl alcohol(InSe-PVA)film is employed as saturable ...Indium selenide(InSe)is a typical layered metal-chalcogenide semiconductor that has potential for developing ultrafast optoelectronic devices.In this work,InSe-polyvinyl alcohol(InSe-PVA)film is employed as saturable absorber and prepared by mixing InSe nanosheets solution and polyvinyl alcohol solution.The nonlinear absorption properties of the InSe saturable absorber(InSe-SA)are investigated,showing that the nonsaturable absorption and modulation depth are 37.5%and 9.55%,respectively.Traditional soliton lasers are generated in erbium-doped fiber(EDF)laser-employed InSe as a mode-locker.The central wavelength and pulse duration of the traditional soliton pulse are 1568.73 nm and 2.06 ps,respectively,under a repetition rate of 1.731 MHz.The maximum average output power is 16.4 mW at the pump power of 413 mW.To the best of our knowledge,this is the first demonstration of a traditional soliton pulse with InSe as a mode-locker.The experimental results further demonstrate that InSe is an outstanding nonlinear absorption material in ultrafast fiber laser.展开更多
基金supported by the National Natural Science Foundation of China programs(52007110,22078179,21901146)the Natural Science Foundation of Shandong Province(ZR2020QB048)the Taishan Scholar Foundation(tsqn201812063)。
文摘Silicon is emerging as a promising next-generation lithium-ion battery anode because of its high theoretical capacity and low cost.However,the poor cyclability and inferior rate performance hinder its largescale applications.Here,hollow silicon/germanium(H-SiGe)nanospheres with a binary-active component and heterogeneous structure combined with porous carbon(pC)reinforcing are synthesized as lithium-ion battery anodes.Experimental studies demonstrate that the H-SiGe/pC anodes possess tiny volume expansion,high ion/electron conductivity,and stable electrode interface.Theoretical calculations confirm that through the replacement of Si using Ge with rational component control,the diffusion energy barrier of lithium will be reduced and lithium storage ability can be improved because of the slight charge polarization.Benefiting from these unique merits,the H-SiGe/pC anodes display a high initial specific capacity of 2922.2 mA h g^(-1)at 0.1 A g^(-1),superior rate capability(59.4%capacity retention from 0.5 to 8 A g^(-1)),and excellent cycling stability(81%retention after 700 cycles at 5 A g^(-1)at 1.0–1.2 mg cm^(-2)).An outstanding stability is preserved even at a high loading of 3.2 mg cm^(-2)with an improved reversible capacity of 429.1 mA h g^(-1)after 500 cycles at 4 A g^(-1).Furthermore,the full-cell with the prelithiated H-SiGe/pC anode and LiFePO4cathode exhibits an impressive capacity performance.
文摘<span style="font-family:Verdana;">T</span><span style="font-family:Verdana;font-size:12px;">he T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">nanosheets</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> prepared by means of ultrasound-assisted liquid </span><span style="font-family:Verdana;font-size:12px;">phase exfoliation (LPE)</span><span style="font-family:Verdana;font-size:12px;"> and the </span><span style="font-family:Verdana;font-size:12px;">nonlinear </span><span style="font-family:Verdana;font-size:12px;">saturable absorption</span><span style="font-family:Verdana;font-size:12px;"> properties</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">were experimentally</span><span style="font-family:Verdana;font-size:12px;"> investigated. The modulation depth, saturation intensity and nonsaturable absorbance</span><span style="font-family:Verdana;font-size:12px;"> of the prepared </span><span style="font-family:Verdana;font-size:12px;">1T-TiSe</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">SA </span><span style="font-family:Verdana;font-size:12px;">were</span><span style="font-family:Verdana;font-size:12px;"> </span><span style="font-family:Verdana;font-size:12px;">1</span><span style="font-family:Verdana;font-size:12px;">5.7</span><span style="font-family:Verdana;font-size:12px;">%,</span><span style="font-family:Verdana;font-size:12px;"> 1.28 M</span><span style="font-family:Verdana;font-size:12px;">W/cm</span><sup><span style="font-family:Verdana;font-size:12px;vertical-align:super;">2</span></sup><span style="font-family:Verdana;font-size:12px;"> and 8.</span><span style="font-family:Verdana;font-size:12px;">2</span><span style="font-family:Verdana;font-size:12px;">%, </span><span style="font-family:Verdana;font-size:12px;">respectively</span><span style="font-family:Verdana;font-size:12px;">. Taking advantage of the saturable absorption properties of </span><span style="font-family:Verdana;font-size:12px;">T</span><span style="font-family:Verdana;font-size:12px;">i</span><span style="font-family:Verdana;font-size:12px;">Se</span><sub><span style="font-family:Verdana;font-size:12px;">2</span></sub><span style="font-family:Verdana;font-size:12px;">-based SA, a passively Q-switched erbium-doped fiber (EDF) laser was</span><span style="font-family:Verdana;font-size:12px;"> systematically demonstrated</span><span style="font-family:Verdana;font-size:12px;">. The pulse repetition rates varied from 24.50 kHz up to 73.79 kHz with the increasing pump power. The obtained shortest pulse width was 1.31 </span><span style="font-family:Verdana;font-size:12px;">μ</span><span style="font-family:Verdana;font-size:12px;">s with pulse energy of 79.28 nJ. The </span><span style="font-family:Verdana;font-size:12px;">system presented merits of low-cost SA preparation, system compactness,</span><span style="font-family:Verdana;font-size:12px;"> superb stability and high competition.</span>
基金supported by the National Natural Science Foundation of China(Grant Nos.61971271,11904213,and 11747149)the Jinan City-School Integration Development Strategy Project(Grant No.JNSX2021023)+4 种基金the Shandong Province Major Technological Innovation Project(Grant No.2022CXGC010502)the Shandong Province Natural Science Foundation(Grant No.ZR2018QF006)the Key Project of Department of Education of Guangdong Province(Grant No.2018KCXTD026)the Deanship of Scientific Research(DSR)at King Abdulaziz University,Jeddah(Grant No.KEP-MSc-70-130-42)the“Opening Foundation of Shandong Provincial Key Laboratory of Laser Technology and Application”.
文摘Niobium telluride(NbTe_(2)),an emerging transition metal dichalcogenide material,has been theoretically predicted to have nonlinear absorption properties and excellent optical response.However,only a few studies of the utilization of NbTe_(2)in ultrafast photonics have been reported.In this work,a NbTe_(2)-based saturable absorber(SA)was applied in an erbium-doped fiber as a mode-locked device,and a vector soliton based on NbTe_(2)was obtained for the first time.NbTe_(2)-PVA film SA was successfully prepared by the liquid-phase exfoliation and spin coating methods,with a modulation depth of up to 10.87%.The nonlinear absorption coefficient of NbTe_(2)-based SA film tested through the open-aperture Z-scan laser measurement is 0.62×10^(−11) m/W.A conventional soliton with a pulse duration of 858 fs was generated using NbTe_(2)-based SA,which was demonstrated to be a kind of polarization-locked vector soliton in further investigation.Our experimental results reveal the nonlinear optical properties of NbTe_(2)and broaden its applications in ultrafast photonic devices.
基金funded by the National Natural Science Foundation of China(Grant No.62005094)the Natural Science Foundation of Shandong Province(No.ZR2021MF128)+1 种基金the Key research program of Shandong Province(2020JMRH0302)the Industrial Chain Program of Shandong laser Equipment Innovation and Entrepreneurship Community(JGCYL2022-5).
文摘As a member of Xenes family,germanene has excellent nonlinear saturable absorption characteristics.In this work,we prepared germanene nanosheets by liquid phase exfoliation and measured their saturation intensity as 0.6 GW/cm^(2) with a modulation depth of 8%.Then,conventional solitons with a pulse width of 946 fs and high-energy noise-like pulses with a pulse width of 784 fs were obtained by using germanene nanosheet as a saturable absorber for a mode-locked Erbium-doped fber laser.The characteristics of the two types of pulses were investigated experimentally.The results reveal that germanene has great potential for modulation devices in ultrafast lasers and can be used as a material for creation of excellent nonlinear optical devices to explore richer applications in ultrafast photonics.
基金Project supported by the National Natural Science Foundation of China(Nos.11904213 and 11747149)the Shandong Provincial Natural Science Foundation(Nos.ZR2018QF006 and ZR2019MF029)+1 种基金the China Postdoctoral Science Foundation(No.2016M602177)the Opening Foundation of Shandong Provincial Key Laboratory of Laser Technology and Application。
文摘In this study,titanium disulfide(TiS_(2))polyvinyl alcohol(PVA)film-type saturable absorber(SA)is synthesized with a modulation depth of 5.08%and a saturable intensity of 10.62 MW/cm^(2) by liquid-phase exfoliation and spin-coating methods.Since TiS2-based SA has a strong nonlinear saturable absorption property,two types of optical soliton were observed in a mode-locked Er-doped fiber laser.When the pump power was raised to 67.3 mW,a conventional mode-locked pulse train with a repetition rate of 1.716 MHz and a pulse width of 6.57 ps was generated,and the output spectrum centered at 1556.98 nm and 0.466 nm spectral width with obvious Kelly sidebands was obtained.Another type of mode-locked pulse train with the maximum output power of 3.92 mW and pulse energy of 2.28 nJ at the pump power of 517.2 mW was achieved when the polarization controllers were adjusted.Since TiS2-based SA has excellent nonlinear saturable absorption characteristics,broad applications in ultrafast photonic are expected.
基金Project supported by the National Natural Science Foundation of China(Nos.11904213,11704226,and 11704227)。
文摘Indium selenide(InSe)is a typical layered metal-chalcogenide semiconductor that has potential for developing ultrafast optoelectronic devices.In this work,InSe-polyvinyl alcohol(InSe-PVA)film is employed as saturable absorber and prepared by mixing InSe nanosheets solution and polyvinyl alcohol solution.The nonlinear absorption properties of the InSe saturable absorber(InSe-SA)are investigated,showing that the nonsaturable absorption and modulation depth are 37.5%and 9.55%,respectively.Traditional soliton lasers are generated in erbium-doped fiber(EDF)laser-employed InSe as a mode-locker.The central wavelength and pulse duration of the traditional soliton pulse are 1568.73 nm and 2.06 ps,respectively,under a repetition rate of 1.731 MHz.The maximum average output power is 16.4 mW at the pump power of 413 mW.To the best of our knowledge,this is the first demonstration of a traditional soliton pulse with InSe as a mode-locker.The experimental results further demonstrate that InSe is an outstanding nonlinear absorption material in ultrafast fiber laser.
