Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stab...Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.展开更多
Sodium-ion batteries(SIBs)have rapidly risen to the forefront of energy storage systems as a promising supplementary for Lithium-ion batteries(LIBs).Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)as a common cathode of SIBs,featur...Sodium-ion batteries(SIBs)have rapidly risen to the forefront of energy storage systems as a promising supplementary for Lithium-ion batteries(LIBs).Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)as a common cathode of SIBs,features the merits of high operating voltage,small volume change and favorable specific energy density.However,it suffers from poor cycling stability and rate performance induced by its low intrinsic conductivity.Herein,we propose an ingenious strategy targeting superior SIBs through cross-linked NVPF with multi-dimensional nanocarbon frameworks composed of amorphous carbon and carbon nanotubes(NVPF@C@CNTs).This rational design ensures favorable particle size for shortened sodium ion transmission pathway as well as improved electronic transfer network,thus leading to enhanced charge transfer kinetics and superior cycling stability.Benefited from this unique structure,significantly improved electrochemical properties are obtained,including high specific capacity(126.9 mAh g^(-1)at 1 C,1 C=128 mA g^(-1))and remarkably improved long-term cycling stability with 93.9%capacity retention after 1000 cycles at 20 C.The energy density of 286.8 Wh kg^(-1)can be reached for full cells with hard carbon as anode(NVPF@C@CNTs//HC).Additionally,the electrochemical performance of the full cell at high temperature is also investigated(95.3 mAh g^(-1)after 100 cycles at 1 C at 50℃).Such nanoscale dual-carbon networks engineering and thorough discussion of ion diffusion kinetics might make contributions to accelerating the process of phosphate cathodes in SIBs for large-scale energy storages.展开更多
采用改进的溶胶凝胶燃烧法成功合成了Y^(3+)掺杂的多孔Na_(3)V_(2)(PO_(4))_(3)/C(记为NVP/C)复合材料,运用XRD、BET、SEM、HRTEM和电化学测试等手段对其进行结构表征和储钠性能测试。结果表明,半径较大的Y^(3+)取代NVP晶体结构中的部分...采用改进的溶胶凝胶燃烧法成功合成了Y^(3+)掺杂的多孔Na_(3)V_(2)(PO_(4))_(3)/C(记为NVP/C)复合材料,运用XRD、BET、SEM、HRTEM和电化学测试等手段对其进行结构表征和储钠性能测试。结果表明,半径较大的Y^(3+)取代NVP晶体结构中的部分V^(3+)导致晶格膨胀,扩大了Na^(+)的传输通道,加快了Na^(+)的迁移。在制备改性样品过程中,Y^(3+)与PO_(4)^(3-)发生反应,生成新的导电相YPO_(4),提高了复合材料的电子电导率。此外,Y^(3+)掺杂使得不规则多边形NVP颗粒球化并且尺寸略有减小。得益于适当的Y^(3+)掺杂量以及均匀的无定形碳包覆层和多孔结构,NVP/C-Y0.10样品具有优异的储钠性能,其在5 C高倍率下的首次放电比容量高达96.3 m A·h/g,经1000次循环后仍能保持82.2 m A·h/g的可逆容量。展开更多
Heterojunction construction,especially S-scheme heterojunction,represents an efficient universal strategy to achieve high-performance photocatalytic materials.For further performance stimulation of these well-designed...Heterojunction construction,especially S-scheme heterojunction,represents an efficient universal strategy to achieve high-performance photocatalytic materials.For further performance stimulation of these well-designed heterojunctions,modulating the interfacial internal electric field(IEF)to steer dynamic charge transfer represents a promising approach.Herein,we realized the precise regulation of Fermi level(E_(F))of the oxidation semiconductor(mesoporous WO_(3-x))by tailoring the concentration of oxygen vacancies(V_(O)),maximizing the IEF intensity in Cs_(2)CuBr_(4)@WO_(3-x)(CCB@WO_(3-x))S-scheme heterojunction.The augmented IEF affords a robust driving force for directional electron delivery,leading to boosted charge separation.Hence,the developed CCB@WO_(3-x)S-scheme heterojunction demonstrated outstanding photocatalytic CO_(2)reduction performance,with the electron consumption rate(Relectron)up to 390.34μmol g^(-1)h^(-1),which is 3.28 folds higher than that of pure CCB.An in-depth analysis of the S-scheme electron transfer mode was presented via theoretical investigations,electron spin resonance(ESR),photo-irradiated Kelvin probe force microscopy(KPFM),and in-situ X-ray photoelectron spectroscopy(XPS).Finally,the CO_(2)photoconversion route was explored in detail using in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and DFT theoretical calculations.展开更多
Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF) is shown to be an attractive cathode material for sodium storage due to its high theoretical capacity and suitable working voltage.However,its low electronic conductivity and poor cy...Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF) is shown to be an attractive cathode material for sodium storage due to its high theoretical capacity and suitable working voltage.However,its low electronic conductivity and poor cycling stability have to be addressed in order for enhanced high-rate performance and cycle life.Herein,we have prepared a 3D reduced graphene oxide (rGO) host-supported NVPF nanocuboids.We discover that polyvinyl alcohol (PVA) serves as an important structural directing agent that bridges between NVPF and rGO through the hydrogen bonding,and thus regulates the formation of the 3D r GO framework with NVPF nanocuboids embedded inside (NVPF@C@rGO).With such a unique construction,NVPF@C@rGO exhibits excellent cycling stability and rate performance for sodium storage,showing high reversible capacities of 121 m Ah/g and 113 mAh/g at 1C and 10C,respectively,and 103 mAh/g after 700cycles at 50C with 98.3%retention.Even at an extremely high current of 100C,it also delivers a reversible capacity of 64 mAh/g,surpassing the performance of many recently reported NVPF-based electrodes.Cyclic voltammetry (CV) and galvanostatic intermittent titration technique (GITT) data confirm the much better kinetic properties of NVPF@C@rGO electrode than the control samples of NVPF@rGO and pure NVPF.In-situ XRD results reveal that the 3D rGO housing can effectively suppress the lattice variation of NVPF,with a maximum volume change of only 1.84%during cycling.Moreover,the in-situ temperature sensing reveals the more stable working temperature of NVPF@C@rGO compared to phase-pure NVPF,suggesting a higher temperature safety of the electrode.Using NVPF@C@rGO as the positive electrode and commercial hard carbon as the negative electrode,a sodium-ion full battery has been assembled with about 110 m Ah/g at 1C for 300 cycles,corresponding to an energy density of 291 Wh kg^(-1).The construction of 3D r GO housing as a conductive support offers an effective strategy for high-rate,long cycle life and high safety sodium-ion battery cathodes.展开更多
基金partly supported by the National Natural Science Foundation of China(Grant No.52272225).
文摘Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.
基金financially supported by Science and Technology Foundation of Guizhou Province(QKHZC[2020]2Y037)the Science and Technology Innovation Program of Hunan Province(2020RC4005,2019RS1004)+2 种基金Research start-up funding from Central South University(202044019)Innovation Mover Program of Central South University(2020CX007)National Natural Science Foundation of China(U21A20284)
文摘Sodium-ion batteries(SIBs)have rapidly risen to the forefront of energy storage systems as a promising supplementary for Lithium-ion batteries(LIBs).Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)as a common cathode of SIBs,features the merits of high operating voltage,small volume change and favorable specific energy density.However,it suffers from poor cycling stability and rate performance induced by its low intrinsic conductivity.Herein,we propose an ingenious strategy targeting superior SIBs through cross-linked NVPF with multi-dimensional nanocarbon frameworks composed of amorphous carbon and carbon nanotubes(NVPF@C@CNTs).This rational design ensures favorable particle size for shortened sodium ion transmission pathway as well as improved electronic transfer network,thus leading to enhanced charge transfer kinetics and superior cycling stability.Benefited from this unique structure,significantly improved electrochemical properties are obtained,including high specific capacity(126.9 mAh g^(-1)at 1 C,1 C=128 mA g^(-1))and remarkably improved long-term cycling stability with 93.9%capacity retention after 1000 cycles at 20 C.The energy density of 286.8 Wh kg^(-1)can be reached for full cells with hard carbon as anode(NVPF@C@CNTs//HC).Additionally,the electrochemical performance of the full cell at high temperature is also investigated(95.3 mAh g^(-1)after 100 cycles at 1 C at 50℃).Such nanoscale dual-carbon networks engineering and thorough discussion of ion diffusion kinetics might make contributions to accelerating the process of phosphate cathodes in SIBs for large-scale energy storages.
文摘采用改进的溶胶凝胶燃烧法成功合成了Y^(3+)掺杂的多孔Na_(3)V_(2)(PO_(4))_(3)/C(记为NVP/C)复合材料,运用XRD、BET、SEM、HRTEM和电化学测试等手段对其进行结构表征和储钠性能测试。结果表明,半径较大的Y^(3+)取代NVP晶体结构中的部分V^(3+)导致晶格膨胀,扩大了Na^(+)的传输通道,加快了Na^(+)的迁移。在制备改性样品过程中,Y^(3+)与PO_(4)^(3-)发生反应,生成新的导电相YPO_(4),提高了复合材料的电子电导率。此外,Y^(3+)掺杂使得不规则多边形NVP颗粒球化并且尺寸略有减小。得益于适当的Y^(3+)掺杂量以及均匀的无定形碳包覆层和多孔结构,NVP/C-Y0.10样品具有优异的储钠性能,其在5 C高倍率下的首次放电比容量高达96.3 m A·h/g,经1000次循环后仍能保持82.2 m A·h/g的可逆容量。
基金This work was financially supported by the National Natural Science Foundation of China(51972213)Natural Science Foundation of Shanghai(22ZR1460700).
文摘Heterojunction construction,especially S-scheme heterojunction,represents an efficient universal strategy to achieve high-performance photocatalytic materials.For further performance stimulation of these well-designed heterojunctions,modulating the interfacial internal electric field(IEF)to steer dynamic charge transfer represents a promising approach.Herein,we realized the precise regulation of Fermi level(E_(F))of the oxidation semiconductor(mesoporous WO_(3-x))by tailoring the concentration of oxygen vacancies(V_(O)),maximizing the IEF intensity in Cs_(2)CuBr_(4)@WO_(3-x)(CCB@WO_(3-x))S-scheme heterojunction.The augmented IEF affords a robust driving force for directional electron delivery,leading to boosted charge separation.Hence,the developed CCB@WO_(3-x)S-scheme heterojunction demonstrated outstanding photocatalytic CO_(2)reduction performance,with the electron consumption rate(Relectron)up to 390.34μmol g^(-1)h^(-1),which is 3.28 folds higher than that of pure CCB.An in-depth analysis of the S-scheme electron transfer mode was presented via theoretical investigations,electron spin resonance(ESR),photo-irradiated Kelvin probe force microscopy(KPFM),and in-situ X-ray photoelectron spectroscopy(XPS).Finally,the CO_(2)photoconversion route was explored in detail using in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and DFT theoretical calculations.
基金financially supported by the National Natural Science Foundation of China (No. 52372176)Guangdong Basic and Applied Basic Research Foundation (No. 2024A1515011517)。
文摘Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF) is shown to be an attractive cathode material for sodium storage due to its high theoretical capacity and suitable working voltage.However,its low electronic conductivity and poor cycling stability have to be addressed in order for enhanced high-rate performance and cycle life.Herein,we have prepared a 3D reduced graphene oxide (rGO) host-supported NVPF nanocuboids.We discover that polyvinyl alcohol (PVA) serves as an important structural directing agent that bridges between NVPF and rGO through the hydrogen bonding,and thus regulates the formation of the 3D r GO framework with NVPF nanocuboids embedded inside (NVPF@C@rGO).With such a unique construction,NVPF@C@rGO exhibits excellent cycling stability and rate performance for sodium storage,showing high reversible capacities of 121 m Ah/g and 113 mAh/g at 1C and 10C,respectively,and 103 mAh/g after 700cycles at 50C with 98.3%retention.Even at an extremely high current of 100C,it also delivers a reversible capacity of 64 mAh/g,surpassing the performance of many recently reported NVPF-based electrodes.Cyclic voltammetry (CV) and galvanostatic intermittent titration technique (GITT) data confirm the much better kinetic properties of NVPF@C@rGO electrode than the control samples of NVPF@rGO and pure NVPF.In-situ XRD results reveal that the 3D rGO housing can effectively suppress the lattice variation of NVPF,with a maximum volume change of only 1.84%during cycling.Moreover,the in-situ temperature sensing reveals the more stable working temperature of NVPF@C@rGO compared to phase-pure NVPF,suggesting a higher temperature safety of the electrode.Using NVPF@C@rGO as the positive electrode and commercial hard carbon as the negative electrode,a sodium-ion full battery has been assembled with about 110 m Ah/g at 1C for 300 cycles,corresponding to an energy density of 291 Wh kg^(-1).The construction of 3D r GO housing as a conductive support offers an effective strategy for high-rate,long cycle life and high safety sodium-ion battery cathodes.
