Hard carbons are promising anode materials for sodium-ion batteries.To meet practical requirements,searching for durable and conductive carbon with a stable interface is of great importance.Here,we prepare a series of...Hard carbons are promising anode materials for sodium-ion batteries.To meet practical requirements,searching for durable and conductive carbon with a stable interface is of great importance.Here,we prepare a series of vanadiummodified hard carbon submicrospheres by using hydrothermal carbonization followed by high-temperature pyrolysis.Significantly,the introduction of vanadium can facilitate the nucleation and uniform growth of carbon spheres and generate abundant V-O-C interface bonds,thus optimizing the reaction kinetic.Meanwhile,the optimized hard carbon spheres modified by vanadium carbide,with sufficient pseudographitic domains,provide more active sites for Na ion migration and storage.As a result,the HC/VC-1300 electrode exhibits excellent Na storage performance,including a high capacity of 420 mAh g^(-1) at 50mA g^(-1) and good rate capability at 1 A g^(-1).This study proposes a new strategy for the synthesis of hard carbon spheres with high tap density and emphasizes the key role of pseudographitic structure for Na storage and interface stabilization.展开更多
柔性钠离子电池(SIBs)在便携式和可穿戴设备中具有巨大的应用潜力,因为它们在特定情况下具有适用性和价格优势.在正极材料中,磷酸盐电极材料具有结构稳定性好、工作电位高和寿命长的优点.然而,由于对制造要求苛刻,反应复杂,以及柔性基...柔性钠离子电池(SIBs)在便携式和可穿戴设备中具有巨大的应用潜力,因为它们在特定情况下具有适用性和价格优势.在正极材料中,磷酸盐电极材料具有结构稳定性好、工作电位高和寿命长的优点.然而,由于对制造要求苛刻,反应复杂,以及柔性基材的缺失等问题,柔性磷酸盐电极材料的设计仍然是一个巨大的挑战.在此,我们报道了在柔性多孔碳纳米纤维上垂直生长的VO_(2)纳米片原位转化为三维氟磷酸钒钠纳米棒阵列(PCNF@NVOPF NR).PCNF@NVOPF NR实现了兼具柔性与高压正极电极的特点,并具有长期循环稳定性(4500次循环后容量保持率为87.6%).阵列结构可以确保快速的钠反应动力学和低界面电阻.此外,PCNF@NVOPF NR//PCNF@VO_(2)NS@C钠离子全电池表现出高能量和功率密度(220.5 W h kg^(-1)和9400 W kg^(-1)).这种用于柔性正极的材料设计策略可促进实用钠离子电池的商业化.展开更多
The development of low-cost and eco-friendly gel polymer electrolytes (GPEs) with a wide window, ideal compatibility, and structural stability is an effective measure to achieve safe high-energy-density lithium-metal ...The development of low-cost and eco-friendly gel polymer electrolytes (GPEs) with a wide window, ideal compatibility, and structural stability is an effective measure to achieve safe high-energy-density lithium-metal batteries. Herein, a biodegradable composite polyacrylonitrile/poly-L-lactic acid nanofiber membrane (PAL) is synthesized and used as a robust skeleton for GPEs. The 3D nanofiber membrane (PAL-3-C12) prepared with an adjusted weight ratio of polyacrylonitrile (PAN)/poly-L-lactic acid (PLLA) and spinning solution concentration delivers decent thermal stability, biodegradability, and liquid electrolyte absorbability. The “passivation effect” of PAN upon lithium metal is effectively alleviated by hydrogen bonds formed in the PAL chains. These advantages enable PAL GPEs to work stably to 5.17 V while maintaining high ionic conductivity as well as excellent corrosion resistance and dielectric properties. The interfacial compatibility of optimized GPEs promotes the stable operation of a Li||PAL-3-C12 GPEs||Li symmetric battery for 1000 h at 0.15 mA cm^(−2)/0.15 mA h cm^(−2), and the LiFePO4 full cell retains capacity retention of 97.63% after 140 cycles at 1C.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:51874362,51932011,52002407Scientific Research Project of Hunan Provincial Department of Education,Grant/Award Number:21B0815。
文摘Hard carbons are promising anode materials for sodium-ion batteries.To meet practical requirements,searching for durable and conductive carbon with a stable interface is of great importance.Here,we prepare a series of vanadiummodified hard carbon submicrospheres by using hydrothermal carbonization followed by high-temperature pyrolysis.Significantly,the introduction of vanadium can facilitate the nucleation and uniform growth of carbon spheres and generate abundant V-O-C interface bonds,thus optimizing the reaction kinetic.Meanwhile,the optimized hard carbon spheres modified by vanadium carbide,with sufficient pseudographitic domains,provide more active sites for Na ion migration and storage.As a result,the HC/VC-1300 electrode exhibits excellent Na storage performance,including a high capacity of 420 mAh g^(-1) at 50mA g^(-1) and good rate capability at 1 A g^(-1).This study proposes a new strategy for the synthesis of hard carbon spheres with high tap density and emphasizes the key role of pseudographitic structure for Na storage and interface stabilization.
基金supported by the National Natural Science Foundation of China(51874362 and 22209208)。
文摘柔性钠离子电池(SIBs)在便携式和可穿戴设备中具有巨大的应用潜力,因为它们在特定情况下具有适用性和价格优势.在正极材料中,磷酸盐电极材料具有结构稳定性好、工作电位高和寿命长的优点.然而,由于对制造要求苛刻,反应复杂,以及柔性基材的缺失等问题,柔性磷酸盐电极材料的设计仍然是一个巨大的挑战.在此,我们报道了在柔性多孔碳纳米纤维上垂直生长的VO_(2)纳米片原位转化为三维氟磷酸钒钠纳米棒阵列(PCNF@NVOPF NR).PCNF@NVOPF NR实现了兼具柔性与高压正极电极的特点,并具有长期循环稳定性(4500次循环后容量保持率为87.6%).阵列结构可以确保快速的钠反应动力学和低界面电阻.此外,PCNF@NVOPF NR//PCNF@VO_(2)NS@C钠离子全电池表现出高能量和功率密度(220.5 W h kg^(-1)和9400 W kg^(-1)).这种用于柔性正极的材料设计策略可促进实用钠离子电池的商业化.
基金supported by the National Natural Science Foundation of China(Grant No.51874362,51932011).
文摘The development of low-cost and eco-friendly gel polymer electrolytes (GPEs) with a wide window, ideal compatibility, and structural stability is an effective measure to achieve safe high-energy-density lithium-metal batteries. Herein, a biodegradable composite polyacrylonitrile/poly-L-lactic acid nanofiber membrane (PAL) is synthesized and used as a robust skeleton for GPEs. The 3D nanofiber membrane (PAL-3-C12) prepared with an adjusted weight ratio of polyacrylonitrile (PAN)/poly-L-lactic acid (PLLA) and spinning solution concentration delivers decent thermal stability, biodegradability, and liquid electrolyte absorbability. The “passivation effect” of PAN upon lithium metal is effectively alleviated by hydrogen bonds formed in the PAL chains. These advantages enable PAL GPEs to work stably to 5.17 V while maintaining high ionic conductivity as well as excellent corrosion resistance and dielectric properties. The interfacial compatibility of optimized GPEs promotes the stable operation of a Li||PAL-3-C12 GPEs||Li symmetric battery for 1000 h at 0.15 mA cm^(−2)/0.15 mA h cm^(−2), and the LiFePO4 full cell retains capacity retention of 97.63% after 140 cycles at 1C.
