KFeSO_(4)F(KFSF)is considered a potential cathode due to the large capacity and low cost.However,the inferior electronic conductivity leads to poor electrochemical performance.Defect engineering can facilitate the ele...KFeSO_(4)F(KFSF)is considered a potential cathode due to the large capacity and low cost.However,the inferior electronic conductivity leads to poor electrochemical performance.Defect engineering can facilitate the electron/ion transfer by tuning electronic structure,thus providing favorable electrochemical performance.Herein,through the regulation of surface defect engineering in reduced graphene oxide(rGO),the Fe–C bonds were formed between KFSF and rGO.The Fe–C bonds formed work in regulating the Fe-3d orbital as well as promoting the migration ability of K ions and increasing the electronic conductivity of KFSF.Thus,the KFSF@rGO delivers a high capacity of 119.6 mAh g^(-1).When matched with a graphite@pitch-derived S-doped carbon anode,the full cell delivers an energy density of 250.5 Wh kg^(-1) and a capacity retention of 81.5%after 400 cycles.This work offers a simple and valid method to develop high-performance cathodes by tuning defect sites.展开更多
钠离子电池中,正极材料至关重要,在很大程度上决定了整个电池的能量密度等性能.层状氧化物是钠离子电池中最有潜力的正极材料之一.然而,层状氧化物仍面临着不可逆相变、容量低、空气稳定性差和循环寿命短等缺点,限制了其实际应用.为了...钠离子电池中,正极材料至关重要,在很大程度上决定了整个电池的能量密度等性能.层状氧化物是钠离子电池中最有潜力的正极材料之一.然而,层状氧化物仍面临着不可逆相变、容量低、空气稳定性差和循环寿命短等缺点,限制了其实际应用.为了解决相关问题,本研究成功制备了中空结构的Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)多面体正极材料.其中,少量的大尺寸钾离子实现了对材料中相应钠离子的取代;镍离子的较高氧化还原电位使得氧化物正极材料能够在空气中稳定保存.在100 mA g^(-1)电流密度下放电100次后,仍可保持115.0 mA h g^(-1)的放电比容量.在500 mA g^(-1)的较大电流密度下,材料仍然可实现104.1 mA h g^(-1)的较高放电比容量.研究结果表明,充放电过程中,氧化物正极材料的P2到O2的相变得到了有效地抑制.同时钾离子在层间的嵌入掺杂,使得氧化物正极的钠离子层间距增大,提升了钠离子的迁移速率.因此,Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)应用于钠离子电池正极时展现出较大的吸引力和应用前景.展开更多
In the field of materials science and engineering,controlling over shape and crystal orientation remains a tremendous challenge.Herein,we realize a nano self-assembly morphology adjustment of Na3V2(PO4)2F3(NVPF)materi...In the field of materials science and engineering,controlling over shape and crystal orientation remains a tremendous challenge.Herein,we realize a nano self-assembly morphology adjustment of Na3V2(PO4)2F3(NVPF)material,based on surface energy evolution by partially replacing V3+with aliovalent Mn2+.Crystal growth direction and surface energy evolution,main factors in inducing the nano self-assembly of NVPF with different shapes and sizes,are revealed by high-resolution transmission electron microscope combined with density functional theory.Furthermore,NVPF with a two-dimensional nanosheet structure(NVPF-NS)exhibits the best rate capability with 68 mAh·g−1 of specific capacity at an ultrahigh rate of 20 C and cycle stability with 80.7%of capacity retention over 1,000 cycles at 1 C.More significantly,when matched with Se@reduced graphene oxide(rGO)anode,NVPF-NS//Se@rGO sodium-ion full cells display a remarkable long-term stability with a high capacity retention of 93.8%after 500 cycles at 0.5 C and−25°C.Consequently,experimental and theoretical calculation results manifest that NVPF-NS demonstrates such superior performances,which can be mainly due to its inherent crystal structure and preferential orientation growth of{001}facets.This work will promise insights into developing novel architectural design strategies for high-performance cathode materials in advanced sodium-ion batteries.展开更多
Sodium-ion batteries(SIBs)are proved as one of the most acceptable candidates for replacing lithium-ion batteries in some fields by virtue of a similar“rocking chair”mechanism and the abundance of sodium.The voltage...Sodium-ion batteries(SIBs)are proved as one of the most acceptable candidates for replacing lithium-ion batteries in some fields by virtue of a similar“rocking chair”mechanism and the abundance of sodium.The voltage,rate performance,and energy density of these batteries are mainly determined by the cath-odes.Hence,a Li-Ni-Co co-substituted P2-Na_(0.67)[Li_(0.1)(Mn_(0.7)Ni_(0.2)Co_(0.1))_(0.9)]O_(2)(NLMNC)with ribbon super-structure is prepared with the aim of multi-ion synergistic modification.Owing to the addition of Ni and Co,the Jahn-Teller distortion of Mn can be suppressed corresponding with the improved structural stability,and a little bit of oxygen redox activities is triggered.When with the substitution of 10%Li,the X-ray diffraction(XRD)peaks of NLMNC show the ribbon superstructure at about 21°and 22°.The smooth charge/discharge profiles of the NLMNC cathode exhibit the solid-solution reaction.In addition,the platform at high voltage disappears corresponding with the existing oxygen redox activities being suppressed which may be related to the ribbon superstructure and the promotion of the Ni redox.Such NLMNC cathode can deliver a reversible discharge capacity of 123.5 mA h g^(-1)at 10 mA g^(-1).Even if the current density increases to 500 mA g^(-1),a reversible discharge capacity of 112.8 mA h g^(-1)still can be ob-tained.The distinguished cycling stability is related to the reversible migration of Li+between the metal oxide layer and the interlayer and low volume change during cycling.It is also needing to be mentioned that the capacity retention of NLMNC cathode is about 94.4%(based on the highest discharge capacity)after 100 cycles.This work presents an effective route to develop high-performance cathodes for SIBs.展开更多
According to the reports of"Top Ten Emerging Technologies in Chemistry 2022"released by the International Union of Pure and Applied Chemistry,sodium-ion battery(SIB)technology is identified as a crucial emer...According to the reports of"Top Ten Emerging Technologies in Chemistry 2022"released by the International Union of Pure and Applied Chemistry,sodium-ion battery(SIB)technology is identified as a crucial emerging technology,indicating its promising development for future energy-storage applications[1].In practical applications,commercialized lithium-ion batteries(LIBs)with lithium cobalt oxide and ternary oxide as cathode materials have assumed a dominant position[2].However,these cathode materials of LIBs are highly dependent on expensive cobalt and nickel,rendering them less sustainable for grid-scale energy storage.Conversely,cathode materials in SIBs appear more sustainable due to their lower dependence on cobalt.Furthermore,the strategic importance of reducing over-dependence on lithium resources cannot be overstated.Hence,SIB technology can serve as one of the potential solutions to mitigate this issue[3].展开更多
基金support from the National Key R&D Program of China(Grant No.2023YFE0202000)National Natural Science Foundation of China(Grant No.52102213)Science Technology Program of Jilin Province(Grant No.20230101128JC).
文摘KFeSO_(4)F(KFSF)is considered a potential cathode due to the large capacity and low cost.However,the inferior electronic conductivity leads to poor electrochemical performance.Defect engineering can facilitate the electron/ion transfer by tuning electronic structure,thus providing favorable electrochemical performance.Herein,through the regulation of surface defect engineering in reduced graphene oxide(rGO),the Fe–C bonds were formed between KFSF and rGO.The Fe–C bonds formed work in regulating the Fe-3d orbital as well as promoting the migration ability of K ions and increasing the electronic conductivity of KFSF.Thus,the KFSF@rGO delivers a high capacity of 119.6 mAh g^(-1).When matched with a graphite@pitch-derived S-doped carbon anode,the full cell delivers an energy density of 250.5 Wh kg^(-1) and a capacity retention of 81.5%after 400 cycles.This work offers a simple and valid method to develop high-performance cathodes by tuning defect sites.
基金financially supported by the National Natural Science Foundation of China(91963118 and 52173246)the Science Technology Program of Jilin Province(20220508141RC)+1 种基金the Science and Technology Development Plan of Suzhou(ZXL2021176)the 111 Project(B13013)。
文摘钠离子电池中,正极材料至关重要,在很大程度上决定了整个电池的能量密度等性能.层状氧化物是钠离子电池中最有潜力的正极材料之一.然而,层状氧化物仍面临着不可逆相变、容量低、空气稳定性差和循环寿命短等缺点,限制了其实际应用.为了解决相关问题,本研究成功制备了中空结构的Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)多面体正极材料.其中,少量的大尺寸钾离子实现了对材料中相应钠离子的取代;镍离子的较高氧化还原电位使得氧化物正极材料能够在空气中稳定保存.在100 mA g^(-1)电流密度下放电100次后,仍可保持115.0 mA h g^(-1)的放电比容量.在500 mA g^(-1)的较大电流密度下,材料仍然可实现104.1 mA h g^(-1)的较高放电比容量.研究结果表明,充放电过程中,氧化物正极材料的P2到O2的相变得到了有效地抑制.同时钾离子在层间的嵌入掺杂,使得氧化物正极的钠离子层间距增大,提升了钠离子的迁移速率.因此,Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)应用于钠离子电池正极时展现出较大的吸引力和应用前景.
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China(Nos.91963118,52173246,and 52102213)the Science Technology Program of Jilin Province(No.20200201066JC)the 111 Project(No.B13013).
文摘In the field of materials science and engineering,controlling over shape and crystal orientation remains a tremendous challenge.Herein,we realize a nano self-assembly morphology adjustment of Na3V2(PO4)2F3(NVPF)material,based on surface energy evolution by partially replacing V3+with aliovalent Mn2+.Crystal growth direction and surface energy evolution,main factors in inducing the nano self-assembly of NVPF with different shapes and sizes,are revealed by high-resolution transmission electron microscope combined with density functional theory.Furthermore,NVPF with a two-dimensional nanosheet structure(NVPF-NS)exhibits the best rate capability with 68 mAh·g−1 of specific capacity at an ultrahigh rate of 20 C and cycle stability with 80.7%of capacity retention over 1,000 cycles at 1 C.More significantly,when matched with Se@reduced graphene oxide(rGO)anode,NVPF-NS//Se@rGO sodium-ion full cells display a remarkable long-term stability with a high capacity retention of 93.8%after 500 cycles at 0.5 C and−25°C.Consequently,experimental and theoretical calculation results manifest that NVPF-NS demonstrates such superior performances,which can be mainly due to its inherent crystal structure and preferential orientation growth of{001}facets.This work will promise insights into developing novel architectural design strategies for high-performance cathode materials in advanced sodium-ion batteries.
基金the National Natural Science Foundation of China(No.52173246)the Science and Tech-nology Development Plan of Suzhou(No.ZXL2022176)Natural Sci-ence Foundation of the Jiangsu Higher Education Institutions(No.22KJA430009)and the“111 Project”(No.B13013).
文摘Sodium-ion batteries(SIBs)are proved as one of the most acceptable candidates for replacing lithium-ion batteries in some fields by virtue of a similar“rocking chair”mechanism and the abundance of sodium.The voltage,rate performance,and energy density of these batteries are mainly determined by the cath-odes.Hence,a Li-Ni-Co co-substituted P2-Na_(0.67)[Li_(0.1)(Mn_(0.7)Ni_(0.2)Co_(0.1))_(0.9)]O_(2)(NLMNC)with ribbon super-structure is prepared with the aim of multi-ion synergistic modification.Owing to the addition of Ni and Co,the Jahn-Teller distortion of Mn can be suppressed corresponding with the improved structural stability,and a little bit of oxygen redox activities is triggered.When with the substitution of 10%Li,the X-ray diffraction(XRD)peaks of NLMNC show the ribbon superstructure at about 21°and 22°.The smooth charge/discharge profiles of the NLMNC cathode exhibit the solid-solution reaction.In addition,the platform at high voltage disappears corresponding with the existing oxygen redox activities being suppressed which may be related to the ribbon superstructure and the promotion of the Ni redox.Such NLMNC cathode can deliver a reversible discharge capacity of 123.5 mA h g^(-1)at 10 mA g^(-1).Even if the current density increases to 500 mA g^(-1),a reversible discharge capacity of 112.8 mA h g^(-1)still can be ob-tained.The distinguished cycling stability is related to the reversible migration of Li+between the metal oxide layer and the interlayer and low volume change during cycling.It is also needing to be mentioned that the capacity retention of NLMNC cathode is about 94.4%(based on the highest discharge capacity)after 100 cycles.This work presents an effective route to develop high-performance cathodes for SIBs.
基金supported by the National Key R&D Program of China(2023YFE0202000)the National Natural Science Foundation of China(52173246)Double-Thousand Talents Plan of Jiangxi Province(jxsq2023102005)。
文摘According to the reports of"Top Ten Emerging Technologies in Chemistry 2022"released by the International Union of Pure and Applied Chemistry,sodium-ion battery(SIB)technology is identified as a crucial emerging technology,indicating its promising development for future energy-storage applications[1].In practical applications,commercialized lithium-ion batteries(LIBs)with lithium cobalt oxide and ternary oxide as cathode materials have assumed a dominant position[2].However,these cathode materials of LIBs are highly dependent on expensive cobalt and nickel,rendering them less sustainable for grid-scale energy storage.Conversely,cathode materials in SIBs appear more sustainable due to their lower dependence on cobalt.Furthermore,the strategic importance of reducing over-dependence on lithium resources cannot be overstated.Hence,SIB technology can serve as one of the potential solutions to mitigate this issue[3].
