Na_(4)Fe_(3)(PO_(4))_(2)(P_(2)O_(7))(NFPP)is currently drawing increased attention as a sodium-ion batteries(SIBs)cathode due to the cost-effective and NASICON-type structure features.Owing to the sluggish electron an...Na_(4)Fe_(3)(PO_(4))_(2)(P_(2)O_(7))(NFPP)is currently drawing increased attention as a sodium-ion batteries(SIBs)cathode due to the cost-effective and NASICON-type structure features.Owing to the sluggish electron and Na~+conductivities,however,its real implementation is impeded by the grievous capacity decay and inferior rate capability.Herein,multivalent cation substituted microporous Na_(3.9)Fe_(2.9)Al_(0.1)(PO_(4))_(2)(P_(2)O_(7))(NFAPP)with wide operation-temperature is elaborately designed through regulating structure/interface coupled electron/ion transport.Greatly,the derived Na vacancy and charge rearrangement induced by trivalent Al^(3+)substitution lower the ions diffusion barriers,thereby endowing faster electron transport and Na^(+)mobility.More importantly,the existing Al-O-P bonds strengthen the local environment and alleviate the volume vibration during(de)sodiation,enabling highly reversible valence variation and structural evolution.As a result,remarkable cyclability(over 10,000 loops),ultrafast rate capability(200 C),and exceptional all-climate stability(-40-60℃)in half/full cells are demonstrated.Given this,the rational work might provide an actionable strategy to promote the electrochemical property of NFPP,thus unveiling the great application prospect of sodium iron mixed phosphate materials.展开更多
通过静电纺丝技术制备了纳米级Sb@CN纤维复合材料,是一种潜在的钾离子电池电极材料.研究结果表明,多孔纳米纤维框架结构与均匀分布的Sb纳米组分之间的协同作用可以有效加速离子迁移速率,并缓解K+嵌入过程中引起的体积膨胀,从而使Sb@CN...通过静电纺丝技术制备了纳米级Sb@CN纤维复合材料,是一种潜在的钾离子电池电极材料.研究结果表明,多孔纳米纤维框架结构与均匀分布的Sb纳米组分之间的协同作用可以有效加速离子迁移速率,并缓解K+嵌入过程中引起的体积膨胀,从而使Sb@CN纳米纤维电极表现出优异的钾储存性能.尤其是其长循环稳定性,在5000 m A g–1电流密度下, 1000次循环后,仍可获得212.7 m Ah g–1的可逆容量,此高循环稳定性是目前高性能钾离子电池应用的关键指标.展开更多
共价硫碳材料优异的储能性能逐渐引起人们的极大关注,然而,在电化学钠储存过程中,化学键的演变机制尚不清楚.本文以苯基磷酸作为碳源和催化剂,硫酸钠为硫源和模板,通过高温热处理,成功制备了具有大量共价键的硫碳材料(HCSC),其中硫主要...共价硫碳材料优异的储能性能逐渐引起人们的极大关注,然而,在电化学钠储存过程中,化学键的演变机制尚不清楚.本文以苯基磷酸作为碳源和催化剂,硫酸钠为硫源和模板,通过高温热处理,成功制备了具有大量共价键的硫碳材料(HCSC),其中硫主要以C–S–C和C–S–S–C的短链形式存在.值得注意的是,在储钠过程中,当循环电压低于0.6 V时,大多数桥键会发生电化学裂解,导致在接下来的CV测试中出现了两个可见的氧化还原峰.原位和非原位测试表明,在还原过程中形成了S^2-,同时碳骨架也发生了不可逆的异构化.因此,在接下来的循环过程中(0.01–3.0 V),裂解硫和异构化碳可以共同参与钠的存储.同样,应用于Na-S电池系统中,电压窗口为0.6–2.8 V,在宽电压窗口活化的HCSC也表现出较高的可逆容量(770 mA h g^-1at 300 mA g^-1).这一发现揭示了硫碳桥联化合物的储能机理,也为其他电极材料的表界面化学提供了新的启示.展开更多
二维结构的二硫化钼(MoS2 )是一种很有前景的储能材料,然而从天然辉钼矿中剥离出少片层的二硫化钼层仍是一个难题.本文提出了一种有效的电化学阳离子插层制备少片层MoS2 的策略.通过原位拉曼捕获电化学插层过程中的中间产物(TBA+)xMoS2 ...二维结构的二硫化钼(MoS2 )是一种很有前景的储能材料,然而从天然辉钼矿中剥离出少片层的二硫化钼层仍是一个难题.本文提出了一种有效的电化学阳离子插层制备少片层MoS2 的策略.通过原位拉曼捕获电化学插层过程中的中间产物(TBA+)xMoS2 x-,拉曼映射分析结果表明获得了具有高产率和无相变的少片层MoS2 .值得注意的是,石墨烯的引入进一步增强了剥离的少片层MoS2 的电荷迁移动力学,可以有效增强钠离子的扩散迁移率,缓解MoS2 在充放电过程中的体积变化以及稳定反应产物. E-MoS2 /graphene作为钠离子电池负极材料,其可逆比容量为642.8 mA h g-1(@0.1 A g-1),并表现出优异的倍率性能(比容量分别为447.8和361.9 mA h g-1@1和5 A g-1)以及卓越的长周期循环稳定性,在1 A g-1的电流密度下, 1000次循环后的可逆比容量为328.7 mA h g-1.这种高效的电化学剥离方法也可用于制备其他二维少片层钠离子电池电极材料.展开更多
基金Project(21473258)supported by the National Natural Science Foundation of ChinaProject(13JJ1004)supported by the Distinguished Young Scientists of Hunan Province,ChinaProject(NCET-11-0513)supported by the New Century Excellent Talents in University,China
基金Project(21473258) supported by the National Natural Science Foundation of ChinaProject(13JJ1004) supported by Distinguished Young Scientists of Hunan Province,ChinaProject(NCET-11-0513) supported by Program for the New Century Excellent Talents in University,China
基金supported by the National Natural Science Foundation of China(52325405,52261135632,and U21A20284)the Science and Technology Foundation of Guizhou Province(QKHZC[2020]2Y037)+1 种基金the Fundamental Research Funds for the Central Universities of Central South University(2023XQLH070,2023XQLH069)the U19 station in the National Synchrotron Radiation Laboratory(NSRL)。
文摘Na_(4)Fe_(3)(PO_(4))_(2)(P_(2)O_(7))(NFPP)is currently drawing increased attention as a sodium-ion batteries(SIBs)cathode due to the cost-effective and NASICON-type structure features.Owing to the sluggish electron and Na~+conductivities,however,its real implementation is impeded by the grievous capacity decay and inferior rate capability.Herein,multivalent cation substituted microporous Na_(3.9)Fe_(2.9)Al_(0.1)(PO_(4))_(2)(P_(2)O_(7))(NFAPP)with wide operation-temperature is elaborately designed through regulating structure/interface coupled electron/ion transport.Greatly,the derived Na vacancy and charge rearrangement induced by trivalent Al^(3+)substitution lower the ions diffusion barriers,thereby endowing faster electron transport and Na^(+)mobility.More importantly,the existing Al-O-P bonds strengthen the local environment and alleviate the volume vibration during(de)sodiation,enabling highly reversible valence variation and structural evolution.As a result,remarkable cyclability(over 10,000 loops),ultrafast rate capability(200 C),and exceptional all-climate stability(-40-60℃)in half/full cells are demonstrated.Given this,the rational work might provide an actionable strategy to promote the electrochemical property of NFPP,thus unveiling the great application prospect of sodium iron mixed phosphate materials.
基金supported by the National Natural Science Foundation of China(51904342,51622406,and 21673298)the National Postdoctoral Program for Innovative Talents(BX201600192)+4 种基金Central South University Postdoctoral Foundation(140050018)China Postdoctoral Science Foundation(2017 M6203552)the National Key Research and Development Program of China(2017YFB0102000,2018YFB0104200)Hunan Provincial Science and Technology Plan(2017TP1001)the Fundamental Research Funds for the Central Universities of Central South University(2019zzts431,2019zzts433)。
文摘通过静电纺丝技术制备了纳米级Sb@CN纤维复合材料,是一种潜在的钾离子电池电极材料.研究结果表明,多孔纳米纤维框架结构与均匀分布的Sb纳米组分之间的协同作用可以有效加速离子迁移速率,并缓解K+嵌入过程中引起的体积膨胀,从而使Sb@CN纳米纤维电极表现出优异的钾储存性能.尤其是其长循环稳定性,在5000 m A g–1电流密度下, 1000次循环后,仍可获得212.7 m Ah g–1的可逆容量,此高循环稳定性是目前高性能钾离子电池应用的关键指标.
基金supported by the National Key Research and Development Program of China(2019YFC1907805)the National Natural Science Foundation of China(52004338)+1 种基金Hunan Provincial Natural Science Foundation(2020JJ5696)Guangdong Provincial Department of Natural Resources(2020-011)。
基金supported by the National Key Research and Development Program of China(2017YFB0102003 and2018YFB0104204)the National Natural Science Foundation of China(51622406,21673298 and 21473258)+2 种基金Young Elite Scientists Sponsorship Program By CAST(2017QNRC001)the Project of Innovation Driven Plan in Central South University(2017CX004 and 2018CX005)the Program for Innovative Team(in Science and Technology)in the University of Henan Province of China(17IRTSTHN003)
文摘共价硫碳材料优异的储能性能逐渐引起人们的极大关注,然而,在电化学钠储存过程中,化学键的演变机制尚不清楚.本文以苯基磷酸作为碳源和催化剂,硫酸钠为硫源和模板,通过高温热处理,成功制备了具有大量共价键的硫碳材料(HCSC),其中硫主要以C–S–C和C–S–S–C的短链形式存在.值得注意的是,在储钠过程中,当循环电压低于0.6 V时,大多数桥键会发生电化学裂解,导致在接下来的CV测试中出现了两个可见的氧化还原峰.原位和非原位测试表明,在还原过程中形成了S^2-,同时碳骨架也发生了不可逆的异构化.因此,在接下来的循环过程中(0.01–3.0 V),裂解硫和异构化碳可以共同参与钠的存储.同样,应用于Na-S电池系统中,电压窗口为0.6–2.8 V,在宽电压窗口活化的HCSC也表现出较高的可逆容量(770 mA h g^-1at 300 mA g^-1).这一发现揭示了硫碳桥联化合物的储能机理,也为其他电极材料的表界面化学提供了新的启示.
基金supported by the National Natural Science Foundation of China (51622406, 21673298, and 21473258)the National Key Research and Development Program of China (2017YFB0102000 and 2018YFB0104200)the Project of Innovation Driven Plan in Central South University (2017CX004 and 2018CX005)。
文摘二维结构的二硫化钼(MoS2 )是一种很有前景的储能材料,然而从天然辉钼矿中剥离出少片层的二硫化钼层仍是一个难题.本文提出了一种有效的电化学阳离子插层制备少片层MoS2 的策略.通过原位拉曼捕获电化学插层过程中的中间产物(TBA+)xMoS2 x-,拉曼映射分析结果表明获得了具有高产率和无相变的少片层MoS2 .值得注意的是,石墨烯的引入进一步增强了剥离的少片层MoS2 的电荷迁移动力学,可以有效增强钠离子的扩散迁移率,缓解MoS2 在充放电过程中的体积变化以及稳定反应产物. E-MoS2 /graphene作为钠离子电池负极材料,其可逆比容量为642.8 mA h g-1(@0.1 A g-1),并表现出优异的倍率性能(比容量分别为447.8和361.9 mA h g-1@1和5 A g-1)以及卓越的长周期循环稳定性,在1 A g-1的电流密度下, 1000次循环后的可逆比容量为328.7 mA h g-1.这种高效的电化学剥离方法也可用于制备其他二维少片层钠离子电池电极材料.
基金supported by the National Natural Science Foundation of China(U21A20284)Science and Technology Foundation of Guizhou Province(QKHZC20202Y037)+4 种基金the Science and Technology Innovation Program of Hunan Province(2020RC40052019RS1004)Innovation Mover Program of Central South University(2020CX007)National Research Foundation of Korea(NRF-2017R1A2B3004383)the China Scholarship Council(CSC)for the financial support(202006370306)。
