The state-of-the-art lithium-ion capacitors (LICs),consisting of high-capacity battery-type anode and high-rate capacitor-type cathode,can deliver high energy density and large power density when comparing with tradit...The state-of-the-art lithium-ion capacitors (LICs),consisting of high-capacity battery-type anode and high-rate capacitor-type cathode,can deliver high energy density and large power density when comparing with traditional supercapacitors and lithium-ion batteries,respectively.However,the ion kinetics mismatch between cathode and anode leads to unsatisfied cycling lifetime and anode degradation.Tremendous efforts have been devoted to solving the abovementioned issue.One promising strategy is altering high conductive hard carbon anode with excellent structural stability to match with activated carbon cathode,assembling dual-carbon LIC.In this contribution,one-pot in-situ expansion and heteroatom doping strategy was adopted to prepare sheet-like hard carbon,while activated carbon was obtained involving activation.Ammonium persulfate was used as expanding and doping agent simultaneously.While furfural residues (FR) were served as carbon precursor.The resulting hard carbon (FRNS-HC) and activated carbon (FRNS-AC)show excellent electrochemical performance as negative and positive electrodes in a lithium-ion battery (LIB).To be specific,374.2 m Ah g^(-1)and 123.1 m Ah g^(-1)can be achieved at 0.1 A g^(-1)and 5 A g^(-1)when FRNS-HC was tested as anode.When combined with a highly porous carbon cathode (S_(BET)=2961 m^(2)g^(-1)) synthesized from the same precursor,the LIC showed high specific energy of147.67 Wh kg^(-1)at approximately 199.93 W kg^(-1),and outstanding cycling life with negligible capacitance fading over 1000 cycles.This study could lead the way for the development of heteroatom-doped porous carbon nanomaterials applied to Li-based energy storage applications.展开更多
Sheet-like calcite array and stable vaterite were synthesized by bio-mimetic supported liquid membrane system under different reaction conditions. Both of the FTIR spectra of products showed narrower peak at 1418 cm?1...Sheet-like calcite array and stable vaterite were synthesized by bio-mimetic supported liquid membrane system under different reaction conditions. Both of the FTIR spectra of products showed narrower peak at 1418 cm?1 than that of bulk CaCO3, and that of vaterite has a split in this peak.展开更多
硅是高比能的锂离子电池负极材料,它的比容量十倍于商业化的石墨负极,但是在充放电过程中硅会发生严重的膨胀和收缩,造成电极的不稳定,衰减严重。制备成硅/碳复合电极可以有效提高稳定性,但是在碳材料的选择上仍然缺乏指导性的原则。本...硅是高比能的锂离子电池负极材料,它的比容量十倍于商业化的石墨负极,但是在充放电过程中硅会发生严重的膨胀和收缩,造成电极的不稳定,衰减严重。制备成硅/碳复合电极可以有效提高稳定性,但是在碳材料的选择上仍然缺乏指导性的原则。本研究对比了微米级片状碳材料和微米级球形碳材料对提高硅/碳电极的稳定作用。硅材料选用纳米硅。使用片状碳材料有利于得到稳定的电极,而球形碳正好相反。其原因可能和碳颗粒之间的接触面大小有关系,球形碳颗粒之间的接触面比较小,当填充在碳颗粒间的硅产生膨胀和收缩破坏粘结剂的连接之后,碳颗粒之间失去联系裂开,所以比较容易发生龟裂。而片状石墨的片与片之间接触面比较大,某一处硅的膨胀和收缩产生的裂痕不会影响片与片之间其他部分的连接,电子仍然可以在电极内部顺利地传导,所以它的稳定性比较好。当硅/片状碳中硅质量分数为20%时,经过500次循环后,电极的比容量还有400 mAh g^(-1)左右(100 mA g^(-1)),仍高于石墨的理论比容量。本研究可为硅/碳电极中碳的选用提供参考。展开更多
基金financially supported by the National Natural Science Foundation of China (22075308, 22209197)Natural Science Foundation of Shanxi Province (20210302 1224439, 202203021211002)Shanxi Province Science Foundation for Youths (No: SQ2019001)。
文摘The state-of-the-art lithium-ion capacitors (LICs),consisting of high-capacity battery-type anode and high-rate capacitor-type cathode,can deliver high energy density and large power density when comparing with traditional supercapacitors and lithium-ion batteries,respectively.However,the ion kinetics mismatch between cathode and anode leads to unsatisfied cycling lifetime and anode degradation.Tremendous efforts have been devoted to solving the abovementioned issue.One promising strategy is altering high conductive hard carbon anode with excellent structural stability to match with activated carbon cathode,assembling dual-carbon LIC.In this contribution,one-pot in-situ expansion and heteroatom doping strategy was adopted to prepare sheet-like hard carbon,while activated carbon was obtained involving activation.Ammonium persulfate was used as expanding and doping agent simultaneously.While furfural residues (FR) were served as carbon precursor.The resulting hard carbon (FRNS-HC) and activated carbon (FRNS-AC)show excellent electrochemical performance as negative and positive electrodes in a lithium-ion battery (LIB).To be specific,374.2 m Ah g^(-1)and 123.1 m Ah g^(-1)can be achieved at 0.1 A g^(-1)and 5 A g^(-1)when FRNS-HC was tested as anode.When combined with a highly porous carbon cathode (S_(BET)=2961 m^(2)g^(-1)) synthesized from the same precursor,the LIC showed high specific energy of147.67 Wh kg^(-1)at approximately 199.93 W kg^(-1),and outstanding cycling life with negligible capacitance fading over 1000 cycles.This study could lead the way for the development of heteroatom-doped porous carbon nanomaterials applied to Li-based energy storage applications.
基金Project supported by the National Natural Science Foundation (No. 20471043) of China and Nano-foundation (No. 0259nm021) of Shanghai.
文摘Sheet-like calcite array and stable vaterite were synthesized by bio-mimetic supported liquid membrane system under different reaction conditions. Both of the FTIR spectra of products showed narrower peak at 1418 cm?1 than that of bulk CaCO3, and that of vaterite has a split in this peak.
文摘硅是高比能的锂离子电池负极材料,它的比容量十倍于商业化的石墨负极,但是在充放电过程中硅会发生严重的膨胀和收缩,造成电极的不稳定,衰减严重。制备成硅/碳复合电极可以有效提高稳定性,但是在碳材料的选择上仍然缺乏指导性的原则。本研究对比了微米级片状碳材料和微米级球形碳材料对提高硅/碳电极的稳定作用。硅材料选用纳米硅。使用片状碳材料有利于得到稳定的电极,而球形碳正好相反。其原因可能和碳颗粒之间的接触面大小有关系,球形碳颗粒之间的接触面比较小,当填充在碳颗粒间的硅产生膨胀和收缩破坏粘结剂的连接之后,碳颗粒之间失去联系裂开,所以比较容易发生龟裂。而片状石墨的片与片之间接触面比较大,某一处硅的膨胀和收缩产生的裂痕不会影响片与片之间其他部分的连接,电子仍然可以在电极内部顺利地传导,所以它的稳定性比较好。当硅/片状碳中硅质量分数为20%时,经过500次循环后,电极的比容量还有400 mAh g^(-1)左右(100 mA g^(-1)),仍高于石墨的理论比容量。本研究可为硅/碳电极中碳的选用提供参考。
