Silicone is a kind of polymer material with high cross-linked structure,which is com-posed by Si-O-Si main chain.Due to the special molecular chain structure,silicone mate-rials are characterized by oxidation resistan...Silicone is a kind of polymer material with high cross-linked structure,which is com-posed by Si-O-Si main chain.Due to the special molecular chain structure,silicone mate-rials are characterized by oxidation resistance,aging resistance,high and low temperature resistance and chemical corrosion resistance.Moreover,silicone materials have process-able properties,simple forming process,good mechanical property,non-toxic and pollution-free.Therefore,silicone has been widely concerned by researchers at home and abroad.In this paper,the main research progress and application directions of carbon-silicone composite at home and abroad in recent years are reviewed.展开更多
Silicon (Si) is regarded as a promising material for lithium-ion battery anode because of high theoretical capacity. Nevertheless, Si faces particle pulverization and rapid capacity fading due to serious volume change...Silicon (Si) is regarded as a promising material for lithium-ion battery anode because of high theoretical capacity. Nevertheless, Si faces particle pulverization and rapid capacity fading due to serious volume change during the lithiation and the delithiation process. In this work, a silicon/carbon composite constituted to Si powder and carbon nanofiber (CNF) is produced to solve the above issues as a new design structure of anode material. The Si powder was recycled from the silicon slicing waste in photovoltaic industry and the CNF was from dry rice straws. By mixing the purified Si powder with CNF, the composite was synthesized by the freeze-drying method and calcination. In the cyclic test, Si adding with 1 wt% CNF showed 3091 mAh/g capacity in the first cycle and 1079 mAh/g capacity after 100 cycles at the current density of 0.5 A/g, which were both better than pristine Si. SEM images also show the composite structure can eliminate cracks on the surface of the electrode during cycling. CNF attaching on Si particles can increase specific surface area, so binder can easily combine the active materials and the conductive materials together. This strategy enhances the structure stability and prevents the electrode from delamination.展开更多
In the present work,an interconnected sandwich carbon/Si-SiO2/carbon nanospheres composite was prepared by template method and carbon thermal vapor deposition（TVD）.The carbon conductive layer can not only efficientl...In the present work,an interconnected sandwich carbon/Si-SiO2/carbon nanospheres composite was prepared by template method and carbon thermal vapor deposition（TVD）.The carbon conductive layer can not only efficiently improve the electronic conductivity of Si-based anode,but also play a key role in alleviating the negative effect from huge volume expansion over discharge/charge of Si-based anode.The resulting material delivered a reversible capacity of 1094 mAh/g,and exhibited excellent cycling stability.It kept a reversible capacity of 1050 mAh/g over 200 cycles with a capacity retention of 96%.展开更多
Silicon monoxide(SiO) has been considered as one of the most promising anode materials for next generation highenergy-density Li-ion batteries(LiBs) thanks to its high theoretical capacity. However, the poor intrinsic...Silicon monoxide(SiO) has been considered as one of the most promising anode materials for next generation highenergy-density Li-ion batteries(LiBs) thanks to its high theoretical capacity. However, the poor intrinsic electronic conductivity and large volume change during lithium intercalation/de-intercalation restrict its practical applications. Fabrication of SiO/C composites is an effective way to overcome these problems. Herein, a series of micro-sized SiO@C/graphite(Si0@C/G) composite anode materials, with designed capacity of 600 mAh·g-1, are successfully prepared through a pitch pyrolysis reaction method. The electrochemical performance of SiO@C/G composite anodes with different carbon coating contents of 5 wt%, 10 wt%, 15 wt%, and 35 wt% is investigated. The results show that the SiO@C/G composite with15-wt% carbon coating content exhibits the best cycle performance, with a high capacity retention of 90.7% at 25℃ and90.1% at 45 0 C after 100 cycles in full cells with LiNi0.5Co0.2Mn0.3O2 as cathodes. The scanning electron microscope(SEM) and electrochemistry impedance spectroscopy(EIS) results suggest that a moderate carbon coating layer can promote the formation of stable SEI film, which is favorable for maintaining good interfacial conductivity and thus enhancing the cycling stability of SiO electrode.展开更多
Effects of Al- Si addition on hot modulus of rup- ture ~ HMOR） . thermal shock resistance ~ TSR~ . phase composition and mierostructure of low-carbon MgO - C materials were investigated. The results show that： Al an...Effects of Al- Si addition on hot modulus of rup- ture ~ HMOR） . thermal shock resistance ~ TSR~ . phase composition and mierostructure of low-carbon MgO - C materials were investigated. The results show that： Al and Si addition to low-carbon MgO - C materials leads to dramatic increase in MOR at elevated temperatures; it increases from 4 MPa to 11 -21 MPa at 1 200 ℃ and from 2 MPa to 21 -29 MPa at 1 400 ℃. Al and Si addition to low-carbon MgO - C materials also improves TSR： residual strength ratio after thermal shock when △T = 1 200 ℃ is increased,from 44% to 73% - 77%. Al reacts with C and N2 to form, Al4C3 and AlN, Si reacts with C to form SiC. Ultimately. in-situ formed non- oxides increase appreciably with temperature rising and are well interlaced in periclase skeleton structure at 1 300 -1 400 ℃. which is beneficial to thermomechanical properties.展开更多
Silicon(Si)and carbon(C)composites hold the promise for replacing the commercial graphite anode,thus increasing the energy density of lithium-ion batteries(LIBs).To mitigate the formation of SiC,this paper reports a m...Silicon(Si)and carbon(C)composites hold the promise for replacing the commercial graphite anode,thus increasing the energy density of lithium-ion batteries(LIBs).To mitigate the formation of SiC,this paper reports a molten salt electrolysis approach to prepare C-Si composite by the electrolysis of C-SiO2 composites.Unlike the conventional way of making a C coating on Si,C-SiO2 composites were prepared by pyrolyzing the low-cost sucrose and silica.The electrochemical deoxidation of the C-SiO2 composites not only produces nanostructured Si inside the C matrix but also introduces voids between the C and Si owing to the volume shrinkage from converting SiO2 to Si.More importantly,the use of Mg ion-containing molten salts precludes the generation of SiC,and the electrolytic Si@C composite anode delivers a capacity of about 1500 mAh g-1 after 100 cycles at a current density of 500 mA g-1.Further,the Si@C‖LiNi0.6Co0.2Mn0.2O2 full cell delivers a high energy density of 608 Wh kg-1.Overall,the molten salt approach provides a one-step electrochemical way to convert oxides@C to metals@C functional materials.展开更多
本文以管状和盘状两种天然硅藻土作为初始原料,制备了一系列硅藻土衍生硅碳负极材料,并采用X射线衍射仪(XRD)、拉曼光谱(Raman)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)等测试手段系统表征了所制备样品的晶...本文以管状和盘状两种天然硅藻土作为初始原料,制备了一系列硅藻土衍生硅碳负极材料,并采用X射线衍射仪(XRD)、拉曼光谱(Raman)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)等测试手段系统表征了所制备样品的晶体结构、微观形貌及化学组成.将制备的硅藻土衍生硅碳负极材料作为活性物质组装为锂离子电池,对比了管状和盘状两种形貌对其储锂性能的影响,并详细考察了沥青衍生碳包覆层的加入量对硅碳负极材料比容量及循环稳定性的影响.测试结果表明,样品管DE-1∶3和管DE-1∶6在0.2 A g^(-1)较低电流密度下均具有较好的容量保持率,循环500次之后比容量分别可保持443 mAh g^(-1)和414 mAh g^(-1),而样品管DE-1∶6则在0.5 A g^(-1)较大电流密度下具有更好的结构稳定性.展开更多
硅负极材料因具有较高的理论容量(Li22Si5合金相对应4200 mAh/g)、较低的工作电压(0.2~0.3 V vs Li/Li+)和地球上丰富的原材料储备,成为代替石墨负极的理想材料之一。但是,低电导率及在循环过程中发生剧烈体积膨胀导致电极失效问题限制...硅负极材料因具有较高的理论容量(Li22Si5合金相对应4200 mAh/g)、较低的工作电压(0.2~0.3 V vs Li/Li+)和地球上丰富的原材料储备,成为代替石墨负极的理想材料之一。但是,低电导率及在循环过程中发生剧烈体积膨胀导致电极失效问题限制了硅负极材料的进一步发展。因此,本工作通过物理法利用壳聚糖和石墨对纳米硅实现碳包覆和复合,制备壳聚糖/石墨@纳米硅复合材料(C/G@Si复合材料),对C/G@Si复合材料的结构、形貌和电化学性能进行研究。结果表明:随着石墨添加量的提高,C/G@Si复合材料的可逆比容量略微下降,循环性能和导电性能显著提高。当添加50%(质量分数)石墨时,在100 mA/g的电流密度下,C/G@Si复合材料的首次放电比容量为1136.1 mAh/g,循环充放电100次后剩余容量保持在658.5 mAh/g,展示出优异的电化学性能,对进一步推广硅碳负极材料具有一定的参考价值。展开更多
文摘Silicone is a kind of polymer material with high cross-linked structure,which is com-posed by Si-O-Si main chain.Due to the special molecular chain structure,silicone mate-rials are characterized by oxidation resistance,aging resistance,high and low temperature resistance and chemical corrosion resistance.Moreover,silicone materials have process-able properties,simple forming process,good mechanical property,non-toxic and pollution-free.Therefore,silicone has been widely concerned by researchers at home and abroad.In this paper,the main research progress and application directions of carbon-silicone composite at home and abroad in recent years are reviewed.
文摘Silicon (Si) is regarded as a promising material for lithium-ion battery anode because of high theoretical capacity. Nevertheless, Si faces particle pulverization and rapid capacity fading due to serious volume change during the lithiation and the delithiation process. In this work, a silicon/carbon composite constituted to Si powder and carbon nanofiber (CNF) is produced to solve the above issues as a new design structure of anode material. The Si powder was recycled from the silicon slicing waste in photovoltaic industry and the CNF was from dry rice straws. By mixing the purified Si powder with CNF, the composite was synthesized by the freeze-drying method and calcination. In the cyclic test, Si adding with 1 wt% CNF showed 3091 mAh/g capacity in the first cycle and 1079 mAh/g capacity after 100 cycles at the current density of 0.5 A/g, which were both better than pristine Si. SEM images also show the composite structure can eliminate cracks on the surface of the electrode during cycling. CNF attaching on Si particles can increase specific surface area, so binder can easily combine the active materials and the conductive materials together. This strategy enhances the structure stability and prevents the electrode from delamination.
基金supported by the State Key Basic Research Program of PRC(2011CB935903)the National Natural Science Foundation of China(No.20925312)Shanghai Science Technology Committee(13JC1407900)
文摘In the present work,an interconnected sandwich carbon/Si-SiO2/carbon nanospheres composite was prepared by template method and carbon thermal vapor deposition（TVD）.The carbon conductive layer can not only efficiently improve the electronic conductivity of Si-based anode,but also play a key role in alleviating the negative effect from huge volume expansion over discharge/charge of Si-based anode.The resulting material delivered a reversible capacity of 1094 mAh/g,and exhibited excellent cycling stability.It kept a reversible capacity of 1050 mAh/g over 200 cycles with a capacity retention of 96%.
基金Project supported by the State Grid Technology Project,China(study on the mechanism and characterization of lithium dendrite growth in lithium ion batteries,Project No.DG71-17-010)the National Key Research and Development Program of China(Grant No.2017YFB0102004)the National Natural Science Foundation of China(Grant No.51822211)
文摘Silicon monoxide(SiO) has been considered as one of the most promising anode materials for next generation highenergy-density Li-ion batteries(LiBs) thanks to its high theoretical capacity. However, the poor intrinsic electronic conductivity and large volume change during lithium intercalation/de-intercalation restrict its practical applications. Fabrication of SiO/C composites is an effective way to overcome these problems. Herein, a series of micro-sized SiO@C/graphite(Si0@C/G) composite anode materials, with designed capacity of 600 mAh·g-1, are successfully prepared through a pitch pyrolysis reaction method. The electrochemical performance of SiO@C/G composite anodes with different carbon coating contents of 5 wt%, 10 wt%, 15 wt%, and 35 wt% is investigated. The results show that the SiO@C/G composite with15-wt% carbon coating content exhibits the best cycle performance, with a high capacity retention of 90.7% at 25℃ and90.1% at 45 0 C after 100 cycles in full cells with LiNi0.5Co0.2Mn0.3O2 as cathodes. The scanning electron microscope(SEM) and electrochemistry impedance spectroscopy(EIS) results suggest that a moderate carbon coating layer can promote the formation of stable SEI film, which is favorable for maintaining good interfacial conductivity and thus enhancing the cycling stability of SiO electrode.
文摘Effects of Al- Si addition on hot modulus of rup- ture ~ HMOR） . thermal shock resistance ~ TSR~ . phase composition and mierostructure of low-carbon MgO - C materials were investigated. The results show that： Al and Si addition to low-carbon MgO - C materials leads to dramatic increase in MOR at elevated temperatures; it increases from 4 MPa to 11 -21 MPa at 1 200 ℃ and from 2 MPa to 21 -29 MPa at 1 400 ℃. Al and Si addition to low-carbon MgO - C materials also improves TSR： residual strength ratio after thermal shock when △T = 1 200 ℃ is increased,from 44% to 73% - 77%. Al reacts with C and N2 to form, Al4C3 and AlN, Si reacts with C to form SiC. Ultimately. in-situ formed non- oxides increase appreciably with temperature rising and are well interlaced in periclase skeleton structure at 1 300 -1 400 ℃. which is beneficial to thermomechanical properties.
基金the financial support from the National Training Program of Innovation and Entrepreneurship for Undergraduates(201810145075)Fundamental Research Funds for the Central Universities(N172505002)+2 种基金NSFC(51704060)National Thousand Youth Talent Program of Chinathe 111 Project(B16009)
文摘Silicon(Si)and carbon(C)composites hold the promise for replacing the commercial graphite anode,thus increasing the energy density of lithium-ion batteries(LIBs).To mitigate the formation of SiC,this paper reports a molten salt electrolysis approach to prepare C-Si composite by the electrolysis of C-SiO2 composites.Unlike the conventional way of making a C coating on Si,C-SiO2 composites were prepared by pyrolyzing the low-cost sucrose and silica.The electrochemical deoxidation of the C-SiO2 composites not only produces nanostructured Si inside the C matrix but also introduces voids between the C and Si owing to the volume shrinkage from converting SiO2 to Si.More importantly,the use of Mg ion-containing molten salts precludes the generation of SiC,and the electrolytic Si@C composite anode delivers a capacity of about 1500 mAh g-1 after 100 cycles at a current density of 500 mA g-1.Further,the Si@C‖LiNi0.6Co0.2Mn0.2O2 full cell delivers a high energy density of 608 Wh kg-1.Overall,the molten salt approach provides a one-step electrochemical way to convert oxides@C to metals@C functional materials.
文摘本文以管状和盘状两种天然硅藻土作为初始原料,制备了一系列硅藻土衍生硅碳负极材料,并采用X射线衍射仪(XRD)、拉曼光谱(Raman)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)等测试手段系统表征了所制备样品的晶体结构、微观形貌及化学组成.将制备的硅藻土衍生硅碳负极材料作为活性物质组装为锂离子电池,对比了管状和盘状两种形貌对其储锂性能的影响,并详细考察了沥青衍生碳包覆层的加入量对硅碳负极材料比容量及循环稳定性的影响.测试结果表明,样品管DE-1∶3和管DE-1∶6在0.2 A g^(-1)较低电流密度下均具有较好的容量保持率,循环500次之后比容量分别可保持443 mAh g^(-1)和414 mAh g^(-1),而样品管DE-1∶6则在0.5 A g^(-1)较大电流密度下具有更好的结构稳定性.
文摘硅负极材料因具有较高的理论容量(Li22Si5合金相对应4200 mAh/g)、较低的工作电压(0.2~0.3 V vs Li/Li+)和地球上丰富的原材料储备,成为代替石墨负极的理想材料之一。但是,低电导率及在循环过程中发生剧烈体积膨胀导致电极失效问题限制了硅负极材料的进一步发展。因此,本工作通过物理法利用壳聚糖和石墨对纳米硅实现碳包覆和复合,制备壳聚糖/石墨@纳米硅复合材料(C/G@Si复合材料),对C/G@Si复合材料的结构、形貌和电化学性能进行研究。结果表明:随着石墨添加量的提高,C/G@Si复合材料的可逆比容量略微下降,循环性能和导电性能显著提高。当添加50%(质量分数)石墨时,在100 mA/g的电流密度下,C/G@Si复合材料的首次放电比容量为1136.1 mAh/g,循环充放电100次后剩余容量保持在658.5 mAh/g,展示出优异的电化学性能,对进一步推广硅碳负极材料具有一定的参考价值。
