The inferior conductivity and drastic volume expansion of silicon still remain the bottleneck in achieving high energy density Lithium-ion Batteries(LIBs).The design of the three-dimensional structure of electrodes by...The inferior conductivity and drastic volume expansion of silicon still remain the bottleneck in achieving high energy density Lithium-ion Batteries(LIBs).The design of the three-dimensional structure of electrodes by compositing silicon and carbon materials has been employed to tackle the above challenges,however,the exorbitant costs and the uncertainty of the conductive structure persist,leaving ample room for improvement.Herein,silicon nanoparticles were innovatively composited with eco-friendly biochar sourced from cotton to fabricate a 3D globally consecutive conductive network.The network serves a dual purpose:enhancing overall electrode conductivity and serving as a scaffold to maintain electrode integrity.The conductivity of the network was further augmented by introducing P-doping at the optimum doping temperature of 350℃.Unlike the local conductive sites formed by the mere mixing of silicon and conductive agents,the consecutive network can affirm the improvement of the conductivity at a macro level.Moreover,first-principle calculations further validated that the rapid diffusion of Li^(+)is attributed to the tailored electronic microstructure and charge rearrangement of the fiber.The prepared consecutive conductive Si@P-doped carbonized cotton fiber anode outperforms the inconsecutive Si@Graphite anode in both cycling performance(capacity retention of 1777.15 mAh g^(-1) vs.682.56 mAh g^(-1) after 150 cycles at 0.3 C)and rate performance(1244.24 mAh g^(-1) vs.370.28 mAh g^(-1) at 2.0 C).The findings of this study may open up new avenues for the development of globally interconnected conductive networks in Si-based anodes,thereby enabling the fabrication of high-performance LIBs.展开更多
High-frequency electromagnetic waves and electronic products can bring great convenience to people’s life,but lead to a series of electromagnetic interference(EMI)problems,such as great potential dangers to the norma...High-frequency electromagnetic waves and electronic products can bring great convenience to people’s life,but lead to a series of electromagnetic interference(EMI)problems,such as great potential dangers to the normal operation of elec-tronic components and human safety.Therefore,the research of EMI shield-ing materials has attracted extensive attention by the scholars.Among them,polymer-based EMI shielding materials with light weight,high specific strength,and stable properties have become the current mainstream.The construction of 3D conductive networks has proved to be an effective method for the prepara-tion of polymer-based EMI shielding materials with excellent shielding effective-ness(SE).In this paper,the shielding mechanism of polymer-based EMI shield-ing materials with 3D conductive networks is briefly introduced,with emphasis on the preparation methods and latest research progress of polymer-based EMI shielding materials with different 3D conductive networks.The key scientific and technical problems to be solved in the field of polymer-based EMI shielding materials are also put forward.Finally,the development trend and application prospects of polymer-based EMI shielding materials are prospected.展开更多
Synthesizing multi-component composites via a straightforward,reliable,and scalable approach has been challenging.Herein,a three-dimensional nitrogen-doped porous carbon decorated with core-shell Ni_(3)Sn_(2)@carbon p...Synthesizing multi-component composites via a straightforward,reliable,and scalable approach has been challenging.Herein,a three-dimensional nitrogen-doped porous carbon decorated with core-shell Ni_(3)Sn_(2)@carbon particles(3D N-PC/Ni_(3)Sn_(2)@C)was customized through a simple salt-template pyrolysis approach.The formed Ni_(3)Sn_(2)particles are perfectly surrounded by crystalline carbon layers and em-bedded in 3D carbon walls during pyrolysis.The dual protection of crystalline carbon layers and porous carbon walls guarantees the electrical conductivity and stability of Ni_(3)Sn_(2).The intriguing 3D and core-shell structure coupled with the introduction of multiple components empowers the composite with rich heterogeneous interface and conductive network,and contributes to the lightweight,corrosion resistance,oxidation resistance,and superior stability of electromagnetic(EM)wave absorbers.The N-PC/Ni_(3)Sn_(2)@C possesses the minimum reflection loss(RL min)of-54.01 dB and wide effective absorption bandwidth(EAB)of 7.36 GHz under a low filler content of less than 10%.The concept in the work proposes a facile,eco-friendly,and scalable pathway for the synthesis of other heterogeneous structures of EM wave ab-sorbers.展开更多
Multiphase polymer composites offer a versatile platform for constructing efficient 3D conductive networks by regulating filler distribution.However,controlling the spatial distribution and network formation of 2D fil...Multiphase polymer composites offer a versatile platform for constructing efficient 3D conductive networks by regulating filler distribution.However,controlling the spatial distribution and network formation of 2D fillers like boron nitride(BN)flakes in immiscible polymer blends remains a major challenge for achieving efficient thermal conductivity.This work introduces a strategy to regulate the cross-linking degree of low-density polyethylene(LDPE)in poly(L-lactic acid)(PLLA)/LDPE blends,enabling effective control over BN localization.BN flakes preferentially localize in the LDPE phase,forming double-percolated networks across broad blend compositions.Controlled LDPE cross-linking suppresses domain coalescence and promotes a secondary segregated BN network via capillary bridginginduced agglomeration.This manipulation of domain viscoelasticity enhances 3D filler network formation,increasing the maximum through-plane thermal conductivity of the polymer composites from 2.02 to 2.58 W m^(−1) K^(−1).Our findings offer a facile route for tailoring 3D filler networks in multiphase polymer composites for improved thermal conduction.展开更多
The construction of carbon nanocoil(CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption.However,it is still challengin...The construction of carbon nanocoil(CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption.However,it is still challenging to further enhance the low frequency microwave absorption and elucidate the related loss mechanisms.Herein,the chiral CNCs are first synthesized on a threedimensional(3D)carbon foam and then combined with the FeNi/NiFe_(2)O_(4) nanoparticles to form a novel chiral-dielectric-magnetic trinity foam.The 3D porous CNC-carbon foam network provides excellent impedance matching and strong conduction loss.The formation of the FeNi-carbon interfaces induces interfacial polarization loss,which is confirmed by the density functional theory calculations.Further permeability analysis and the micromagnetic simulation indicate that the nanoscale chiral magnetic heterostructures achieve magnetic pinning and coupling effects,which enhance the magnetic anisotropy and magnetic loss capability.Owing to the synergistic effect between dielectricity,chirality,and magnetism,the trinity composite foam exhibits excellent microwave absorption performance with an ultrabroad effective absorption bandwidth(EAB)of 14 GHz and a minimum reflection of loss less than-50 dB.More importantly,the C-band EAB of the foam is extended to 4 GHz,achieving the full C-band coverage.This study provides further guidelines for the microstructure design of the chiral-dielectric-magnetic trinity composites to achieve broadband microwave absorption.展开更多
A novel in-situ route was employed to synthesize LiFePO4/carbon-nanofibers （CNFs） composites. The route combined high-temperature solid phase reaction with chemical vapor deposition （CVD） using Fe2O3 and LiH2PO4 a...A novel in-situ route was employed to synthesize LiFePO4/carbon-nanofibers （CNFs） composites. The route combined high-temperature solid phase reaction with chemical vapor deposition （CVD） using Fe2O3 and LiH2PO4 as the precursors for LiFePO4 growth and acetylene （C2H2） as the carbon source for CNFs growth. The composites were characterized by X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） specific surface area, field emission scanning electron microscopy （FE-SEM）, and transmission electron microscopy （TEM）. The electrochemical performance of the composites was studied by galvanostatic cycling and cyclic voltammetry （CV）. The results showed that the in-situ CNFs growth could be realized by the catalytic effect of the Fe2O3 precursor. The sample after 80 min CVD reaction showed the best electrochemical performance, indicating a promising application in high-power Li-ion batteries.展开更多
Transition metal oxides gain considerable research attentions as potential anode materials for lithium ion batteries,but their applications are hindered due to their poor electronic conductivity,weak cycle stability a...Transition metal oxides gain considerable research attentions as potential anode materials for lithium ion batteries,but their applications are hindered due to their poor electronic conductivity,weak cycle stability and drastic volume change.Here,a NiO@graphene composite with a unique 3D conductive network structure is prepared through a simple strategy.When applied as anode material for Li-ion batteries,at 50 mA g^(−1),the NiO@graphene displays a high reversible capacity of 1366 mAh g^(−1) and a stable cyclability of 205 mAh g^(−1) after 500 cycles.Even at a high rate of 10 A g^(−1),it displays a favorable reversible capacity of 711 mAh g^(−1).Remarkably,when it recovers back to 0.05 A g^(−1),a reversible capacity of 1741 mAh g^(−1) is achieved.Thus,the NiO@graphene composite with 3D structure shows good application prospects as an alternative anode for advanced lithium ion batteries.展开更多
Currently,the practical application of SiO_(x) still has a huge hindrance in the area of lithium ion battery,because it is unable to achieve an effective contact with surrounding conducting materials,resulting in fail...Currently,the practical application of SiO_(x) still has a huge hindrance in the area of lithium ion battery,because it is unable to achieve an effective contact with surrounding conducting materials,resulting in failure to form lithium ion migration tunnels.In this work,we presented a facile method to synthesize the B-doped SiOx composite by adhering SiO_(x) particles with MWCNT(multi-walled carbon nanotube)under the assistance of lithium metaborate(LiBO_(2)).LiBO_(2),as a sintering aid,not only can react with SiO_(x) to form a compacted framework,but also build a three-dimensional(3D)conductive network for ions transportation.Furthermore,B-SiO_(x)@CNT@LBO anode delivers a remarkable lithium storage performance in terms of long cycles and high rate capability.A full cell coupled with NCM622 cathode achieves a high energy density of 429.5 Wh kg^(-1) based on the total mass of cathode.展开更多
Developing suitable anode materials for potassium-ion batteries(PIBs)remains a great challenge owing to the limited theoretical capacity of active materials and large radius of K+ion(1.38?).To solve these obstacles,by...Developing suitable anode materials for potassium-ion batteries(PIBs)remains a great challenge owing to the limited theoretical capacity of active materials and large radius of K+ion(1.38?).To solve these obstacles,by integrating the principles of multielectron transfer and rational porous crystal framework,we creatively propose the monoclinic Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O(CVO)as a novel anode for PIBs.Furthermore,inspired by the metastable nature of CVO under high temperature/pressure,we skillfully design a facile hydrothermal recrystallization strategy without the phase change and surfactants addition.Thus,for the first time,the porous composite of Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O nanobelts covered in situ by reduced graphene oxide(CVO NBs/r GO)was assembled,greatly improving the deficiencies of CVO.When used as a novel anode for PIBs,CVO NBs/r GO delivers large specific capacity(up to 551.4 m Ah g^(-1)at 50 m A g^(-1)),high-rate capability(215.3 m Ah g^(-1)at 2.5 A g^(-1))and super durability(203.6 m Ah g^(-1)at 500 m A g^(-1)even after 1000 cycles).The outstanding performance can be ascribed to the synergistic merits of desirable structural features of monoclinic CVO nanobelts and the highly conductive graphene 3D network,thus promoting the composite material stability and electrical/ionic conductivity.This work reveals a novel metal vanadate-based anode material for PIBs,would further motivate the subsequent batteries research on M_(3)(OH)_(2)V_(2)O_(7)-n H_(2)O(M;Co,Ni,Cu,Zn),and ultimately expands valuable fundamental understanding on designing other high-performance electrode materials,including the combined strategies of multielectron transfer with rational porous crystal framework,and the composite fabrication of 1D electrode nanostructure with conductive carbon matrix.展开更多
Composite solid electrolytes hold the promise of merging complementary merits of solid polymer electrolytes and ceramic fillers to achieve solid batteries with comprehensive performance.Especially,three-dimensional in...Composite solid electrolytes hold the promise of merging complementary merits of solid polymer electrolytes and ceramic fillers to achieve solid batteries with comprehensive performance.Especially,three-dimensional inorganic electrolyte frameworks,such as Li_(7)La_(3)Zr_(2)O_(12),with fast and continuous lithium ion migration channels demonstrate great promise in composite solid electrolytes.Nevertheless,brittle ceramic conductor skeletons are incapable of providing sufficient mechanical adaptability,which restricts their practical application.Herein,a flexible,ion-conducting network which integrates Li_(7)La_(3)Zr_(2)O_(12)nanoparticles in polyacrylonitrile nanofibers is fabricated through electrospinning method.Subsequently,a composite electrolyte with three-dimensional continuous structure is achieved via in situ polymerizing of 1,3-dioxolane within the ionic conduction framework.The highly conductive Li7La3Zr2O12 reinforced polymer nanofibers are not only available to promote transportation of lithium ion,but also provide structural flexibility and mechanical robustness for composite electrolyte.Accordingly,the obtained composite electrolyte combines enhanced room temperature ionic conductivity(4.38×10^(-4)S·cm^(-1))with structural flexibility and mechanical robustness,supported by exceptional interfacial compatibility with lithium metal,enabling ultra-stable lithium symmetric battery operation(3000 h at 0.1 mA·cm^(-2)).Furthermore,as-prepared LiFePO_(4)and LiCoO_(2)/lithium solid-state batteries deliver high capacity retention of 96%after 350 cycles and capacity retention of 82%after 600 cycles at room temperature.This work provides a new avenue in design of advancing composite solid electrolytes.展开更多
To conquer inherently low conductivity,volume swelling,and labile solid electrolyte interphase(SEI)films of Si anode in lithium ion battery(LIBs),it is widely accepted that appropriate structure design of Si-C hybrids...To conquer inherently low conductivity,volume swelling,and labile solid electrolyte interphase(SEI)films of Si anode in lithium ion battery(LIBs),it is widely accepted that appropriate structure design of Si-C hybrids performs effectively,especially for nanosize Si particles.Herein,inspired by the sturdy construction of high-rise buildings,a mansion-like 3D structured Si@SiO_(2)/PBC/RGO(SSPBG)with separated rooms is developed based on 0D core-shell Si@SiO_(2),1D pyrolytic bacterial cellulose(PBC)and 2D reduced graphene oxide(RGO).Therefore,these hierarchical protectors operate synergistically to inhibit the inevitable volume changes during electrochemical process.Specifically,tightly coated SiO_(2)shell as the first protective layer could buffer the volume expansion and reduce detrimental pulverization of Si NPs.Furthermore,flexible spring-like PBC and ultra-fine RGO sheets perform as securer barriers and skeleton which will counteract the microstructure strain and accelerate electron transfer at the same time.Remarkably,the self-supporting electrode realizes a distinguished performance of 901 mAh g^(-1)at 2 A g^(-1)for 500 cycles.When matched with LiFePO4 cathodes,high stability of more than 100 cycles has been realized for the full batteries.展开更多
基金supported by the National Natural Science Foundation of China(No.12205252)the Basic Public Welfare Re-search Special Project of Zhejiang Province(No.LZY22B040001)+4 种基金the Quzhou Science and Technology Plan Project(No.2022K39)Science and Technology Project of Quzhou Research Institute,Zhejiang University(Nos.IZQ2021KJ2032,IZQ2022KJ3014,and IZQ2022KJ3002)Independent scientific Research Project of Quzhou Research Institute,Zhejiang University(No.IZQ2021RCZX007)New“115 talents”Project ofQuzhou,National Nature Science Foundation of China(No.52172244)Fundamental Research Funds for the Central University(No.226202200053).
文摘The inferior conductivity and drastic volume expansion of silicon still remain the bottleneck in achieving high energy density Lithium-ion Batteries(LIBs).The design of the three-dimensional structure of electrodes by compositing silicon and carbon materials has been employed to tackle the above challenges,however,the exorbitant costs and the uncertainty of the conductive structure persist,leaving ample room for improvement.Herein,silicon nanoparticles were innovatively composited with eco-friendly biochar sourced from cotton to fabricate a 3D globally consecutive conductive network.The network serves a dual purpose:enhancing overall electrode conductivity and serving as a scaffold to maintain electrode integrity.The conductivity of the network was further augmented by introducing P-doping at the optimum doping temperature of 350℃.Unlike the local conductive sites formed by the mere mixing of silicon and conductive agents,the consecutive network can affirm the improvement of the conductivity at a macro level.Moreover,first-principle calculations further validated that the rapid diffusion of Li^(+)is attributed to the tailored electronic microstructure and charge rearrangement of the fiber.The prepared consecutive conductive Si@P-doped carbonized cotton fiber anode outperforms the inconsecutive Si@Graphite anode in both cycling performance(capacity retention of 1777.15 mAh g^(-1) vs.682.56 mAh g^(-1) after 150 cycles at 0.3 C)and rate performance(1244.24 mAh g^(-1) vs.370.28 mAh g^(-1) at 2.0 C).The findings of this study may open up new avenues for the development of globally interconnected conductive networks in Si-based anodes,thereby enabling the fabrication of high-performance LIBs.
基金Foundation of National Natural Science Foundation of China,Grant/Award Number:51903145Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China,Grant/Award Number:2019JC-11Wang L.would like to thank the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,Grant/Award Number:CX202053。
文摘High-frequency electromagnetic waves and electronic products can bring great convenience to people’s life,but lead to a series of electromagnetic interference(EMI)problems,such as great potential dangers to the normal operation of elec-tronic components and human safety.Therefore,the research of EMI shield-ing materials has attracted extensive attention by the scholars.Among them,polymer-based EMI shielding materials with light weight,high specific strength,and stable properties have become the current mainstream.The construction of 3D conductive networks has proved to be an effective method for the prepara-tion of polymer-based EMI shielding materials with excellent shielding effective-ness(SE).In this paper,the shielding mechanism of polymer-based EMI shield-ing materials with 3D conductive networks is briefly introduced,with emphasis on the preparation methods and latest research progress of polymer-based EMI shielding materials with different 3D conductive networks.The key scientific and technical problems to be solved in the field of polymer-based EMI shielding materials are also put forward.Finally,the development trend and application prospects of polymer-based EMI shielding materials are prospected.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2019YQ24)the Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites).
文摘Synthesizing multi-component composites via a straightforward,reliable,and scalable approach has been challenging.Herein,a three-dimensional nitrogen-doped porous carbon decorated with core-shell Ni_(3)Sn_(2)@carbon particles(3D N-PC/Ni_(3)Sn_(2)@C)was customized through a simple salt-template pyrolysis approach.The formed Ni_(3)Sn_(2)particles are perfectly surrounded by crystalline carbon layers and em-bedded in 3D carbon walls during pyrolysis.The dual protection of crystalline carbon layers and porous carbon walls guarantees the electrical conductivity and stability of Ni_(3)Sn_(2).The intriguing 3D and core-shell structure coupled with the introduction of multiple components empowers the composite with rich heterogeneous interface and conductive network,and contributes to the lightweight,corrosion resistance,oxidation resistance,and superior stability of electromagnetic(EM)wave absorbers.The N-PC/Ni_(3)Sn_(2)@C possesses the minimum reflection loss(RL min)of-54.01 dB and wide effective absorption bandwidth(EAB)of 7.36 GHz under a low filler content of less than 10%.The concept in the work proposes a facile,eco-friendly,and scalable pathway for the synthesis of other heterogeneous structures of EM wave ab-sorbers.
基金financially supported by the National Natural Science Foundation of China(Nos.U21A2092,52303079,and U22A20248)the Special Support Plan for High Level Talents in Zhejiang Province(2022R51008).
文摘Multiphase polymer composites offer a versatile platform for constructing efficient 3D conductive networks by regulating filler distribution.However,controlling the spatial distribution and network formation of 2D fillers like boron nitride(BN)flakes in immiscible polymer blends remains a major challenge for achieving efficient thermal conductivity.This work introduces a strategy to regulate the cross-linking degree of low-density polyethylene(LDPE)in poly(L-lactic acid)(PLLA)/LDPE blends,enabling effective control over BN localization.BN flakes preferentially localize in the LDPE phase,forming double-percolated networks across broad blend compositions.Controlled LDPE cross-linking suppresses domain coalescence and promotes a secondary segregated BN network via capillary bridginginduced agglomeration.This manipulation of domain viscoelasticity enhances 3D filler network formation,increasing the maximum through-plane thermal conductivity of the polymer composites from 2.02 to 2.58 W m^(−1) K^(−1).Our findings offer a facile route for tailoring 3D filler networks in multiphase polymer composites for improved thermal conduction.
基金supported by the National Natural Science Foundation of China[Grant Nos.52272288 and 51972039]the China Postdoctoral Science Foundation[No.2021M700658].
文摘The construction of carbon nanocoil(CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption.However,it is still challenging to further enhance the low frequency microwave absorption and elucidate the related loss mechanisms.Herein,the chiral CNCs are first synthesized on a threedimensional(3D)carbon foam and then combined with the FeNi/NiFe_(2)O_(4) nanoparticles to form a novel chiral-dielectric-magnetic trinity foam.The 3D porous CNC-carbon foam network provides excellent impedance matching and strong conduction loss.The formation of the FeNi-carbon interfaces induces interfacial polarization loss,which is confirmed by the density functional theory calculations.Further permeability analysis and the micromagnetic simulation indicate that the nanoscale chiral magnetic heterostructures achieve magnetic pinning and coupling effects,which enhance the magnetic anisotropy and magnetic loss capability.Owing to the synergistic effect between dielectricity,chirality,and magnetism,the trinity composite foam exhibits excellent microwave absorption performance with an ultrabroad effective absorption bandwidth(EAB)of 14 GHz and a minimum reflection of loss less than-50 dB.More importantly,the C-band EAB of the foam is extended to 4 GHz,achieving the full C-band coverage.This study provides further guidelines for the microstructure design of the chiral-dielectric-magnetic trinity composites to achieve broadband microwave absorption.
基金supported by Zijin Program of Zhejiang University, China, the Fundamental Research Funds for the Central Universities (No. 2010QNA4003)the Ph.D. Programs Foundation of Ministry of Education of China (No. 20100101120024)+1 种基金the Foundation of Education Office of Zhejiang Province (No. Y201016484)the Qianjiang Talents Project of Science Technology Department of Zhejiang Province (No. 2011R10021)
文摘A novel in-situ route was employed to synthesize LiFePO4/carbon-nanofibers （CNFs） composites. The route combined high-temperature solid phase reaction with chemical vapor deposition （CVD） using Fe2O3 and LiH2PO4 as the precursors for LiFePO4 growth and acetylene （C2H2） as the carbon source for CNFs growth. The composites were characterized by X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） specific surface area, field emission scanning electron microscopy （FE-SEM）, and transmission electron microscopy （TEM）. The electrochemical performance of the composites was studied by galvanostatic cycling and cyclic voltammetry （CV）. The results showed that the in-situ CNFs growth could be realized by the catalytic effect of the Fe2O3 precursor. The sample after 80 min CVD reaction showed the best electrochemical performance, indicating a promising application in high-power Li-ion batteries.
基金supported by the Science&Technology Department of Sichuan Province(No.2019YJ0665)the Opening Project of Material Corrosion and Protection Key Laboratory of Sichuan Province(No.2020CL10)。
文摘Transition metal oxides gain considerable research attentions as potential anode materials for lithium ion batteries,but their applications are hindered due to their poor electronic conductivity,weak cycle stability and drastic volume change.Here,a NiO@graphene composite with a unique 3D conductive network structure is prepared through a simple strategy.When applied as anode material for Li-ion batteries,at 50 mA g^(−1),the NiO@graphene displays a high reversible capacity of 1366 mAh g^(−1) and a stable cyclability of 205 mAh g^(−1) after 500 cycles.Even at a high rate of 10 A g^(−1),it displays a favorable reversible capacity of 711 mAh g^(−1).Remarkably,when it recovers back to 0.05 A g^(−1),a reversible capacity of 1741 mAh g^(−1) is achieved.Thus,the NiO@graphene composite with 3D structure shows good application prospects as an alternative anode for advanced lithium ion batteries.
基金sponsored by the National Natural Science Foundation of China(21875107,U1802256,51672128,52072173 and 21773118)Jiangsu Specially-Appointed Professors Program,Jiangsu Province Outstanding Youth Fund(SBK2020010215)+4 种基金Leading Edge Technology of Jiangsu Province(BK20202008)Key Research and Development Program in Jiangsu Province(BE2018122)Natural Science Foundation of Jiangsu Province(BK20170778)Fundamental Research Funds for the Central Universities(NE2016005)and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)W.H.acknowledges support from Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX20_0192).
文摘Currently,the practical application of SiO_(x) still has a huge hindrance in the area of lithium ion battery,because it is unable to achieve an effective contact with surrounding conducting materials,resulting in failure to form lithium ion migration tunnels.In this work,we presented a facile method to synthesize the B-doped SiOx composite by adhering SiO_(x) particles with MWCNT(multi-walled carbon nanotube)under the assistance of lithium metaborate(LiBO_(2)).LiBO_(2),as a sintering aid,not only can react with SiO_(x) to form a compacted framework,but also build a three-dimensional(3D)conductive network for ions transportation.Furthermore,B-SiO_(x)@CNT@LBO anode delivers a remarkable lithium storage performance in terms of long cycles and high rate capability.A full cell coupled with NCM622 cathode achieves a high energy density of 429.5 Wh kg^(-1) based on the total mass of cathode.
基金supported by the National Natural Science Foundation of China(52072118,51772089)the Youth 1000 Talent Program of China+3 种基金the Research and Development Plan of Key Areas in Hunan Province(2019GK2235)the Key Research and Development Program of Ningxia(2020BDE03007)the China Postdoctoral Science Foundation(2019M653649)the Guangdong Basic and Applied Basic Research Fund(2019A1515110518,2019A1515111188,2020B0909030004)。
文摘Developing suitable anode materials for potassium-ion batteries(PIBs)remains a great challenge owing to the limited theoretical capacity of active materials and large radius of K+ion(1.38?).To solve these obstacles,by integrating the principles of multielectron transfer and rational porous crystal framework,we creatively propose the monoclinic Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O(CVO)as a novel anode for PIBs.Furthermore,inspired by the metastable nature of CVO under high temperature/pressure,we skillfully design a facile hydrothermal recrystallization strategy without the phase change and surfactants addition.Thus,for the first time,the porous composite of Cu_(3)(OH)_(2)V_(2)O_(7)·2H_(2)O nanobelts covered in situ by reduced graphene oxide(CVO NBs/r GO)was assembled,greatly improving the deficiencies of CVO.When used as a novel anode for PIBs,CVO NBs/r GO delivers large specific capacity(up to 551.4 m Ah g^(-1)at 50 m A g^(-1)),high-rate capability(215.3 m Ah g^(-1)at 2.5 A g^(-1))and super durability(203.6 m Ah g^(-1)at 500 m A g^(-1)even after 1000 cycles).The outstanding performance can be ascribed to the synergistic merits of desirable structural features of monoclinic CVO nanobelts and the highly conductive graphene 3D network,thus promoting the composite material stability and electrical/ionic conductivity.This work reveals a novel metal vanadate-based anode material for PIBs,would further motivate the subsequent batteries research on M_(3)(OH)_(2)V_(2)O_(7)-n H_(2)O(M;Co,Ni,Cu,Zn),and ultimately expands valuable fundamental understanding on designing other high-performance electrode materials,including the combined strategies of multielectron transfer with rational porous crystal framework,and the composite fabrication of 1D electrode nanostructure with conductive carbon matrix.
基金National Key Research and Development Program of China(No.2019YFA0705700)the National Natural Science Foundation of China(No.52472186)。
文摘Composite solid electrolytes hold the promise of merging complementary merits of solid polymer electrolytes and ceramic fillers to achieve solid batteries with comprehensive performance.Especially,three-dimensional inorganic electrolyte frameworks,such as Li_(7)La_(3)Zr_(2)O_(12),with fast and continuous lithium ion migration channels demonstrate great promise in composite solid electrolytes.Nevertheless,brittle ceramic conductor skeletons are incapable of providing sufficient mechanical adaptability,which restricts their practical application.Herein,a flexible,ion-conducting network which integrates Li_(7)La_(3)Zr_(2)O_(12)nanoparticles in polyacrylonitrile nanofibers is fabricated through electrospinning method.Subsequently,a composite electrolyte with three-dimensional continuous structure is achieved via in situ polymerizing of 1,3-dioxolane within the ionic conduction framework.The highly conductive Li7La3Zr2O12 reinforced polymer nanofibers are not only available to promote transportation of lithium ion,but also provide structural flexibility and mechanical robustness for composite electrolyte.Accordingly,the obtained composite electrolyte combines enhanced room temperature ionic conductivity(4.38×10^(-4)S·cm^(-1))with structural flexibility and mechanical robustness,supported by exceptional interfacial compatibility with lithium metal,enabling ultra-stable lithium symmetric battery operation(3000 h at 0.1 mA·cm^(-2)).Furthermore,as-prepared LiFePO_(4)and LiCoO_(2)/lithium solid-state batteries deliver high capacity retention of 96%after 350 cycles and capacity retention of 82%after 600 cycles at room temperature.This work provides a new avenue in design of advancing composite solid electrolytes.
基金supported by the National Natural Science Foundation of China(51802171,52072197)Outstanding Youth Foundation of Shandong Province(ZR2019JQ14)+1 种基金Taishan Scholar Young Talent Program(tsqn201909114)Major Basic Research Program of Natural Science Foundation of Shandong Province(ZR2020ZD09)。
文摘To conquer inherently low conductivity,volume swelling,and labile solid electrolyte interphase(SEI)films of Si anode in lithium ion battery(LIBs),it is widely accepted that appropriate structure design of Si-C hybrids performs effectively,especially for nanosize Si particles.Herein,inspired by the sturdy construction of high-rise buildings,a mansion-like 3D structured Si@SiO_(2)/PBC/RGO(SSPBG)with separated rooms is developed based on 0D core-shell Si@SiO_(2),1D pyrolytic bacterial cellulose(PBC)and 2D reduced graphene oxide(RGO).Therefore,these hierarchical protectors operate synergistically to inhibit the inevitable volume changes during electrochemical process.Specifically,tightly coated SiO_(2)shell as the first protective layer could buffer the volume expansion and reduce detrimental pulverization of Si NPs.Furthermore,flexible spring-like PBC and ultra-fine RGO sheets perform as securer barriers and skeleton which will counteract the microstructure strain and accelerate electron transfer at the same time.Remarkably,the self-supporting electrode realizes a distinguished performance of 901 mAh g^(-1)at 2 A g^(-1)for 500 cycles.When matched with LiFePO4 cathodes,high stability of more than 100 cycles has been realized for the full batteries.
