Solid and hollow microspheres of LiMn_(2)O_(4) have been synthesized by lithiating MnCO_(3) solid microspheres and MnO_(2) hollow microspheres,respectively.The LiMn_(2)O_(4) solid microspheres and hollow microspheres ...Solid and hollow microspheres of LiMn_(2)O_(4) have been synthesized by lithiating MnCO_(3) solid microspheres and MnO_(2) hollow microspheres,respectively.The LiMn_(2)O_(4) solid microspheres and hollow microspheres had a similar size of about 1.5μm,and the shell thickness of the hollow microspheres was only 100 nm.When used as a cathode material in lithium ion batteries,the hollow microspheres exhibited better rate capability than the solid microspheres.However,the tap density of the LiMn_(2)O_(4) solid microspheres(1.0 g/cm^(3))was about four times that of the hollow microspheres(0.27 g/cm^(3)).The results show that controlling the particle size of LiMn_(2)O_(4) is very important in terms of its practical application as a cathode material,and LiMn_(2)O_(4) with moderate particle size may afford acceptable values of both rate capability and tap density.展开更多
Room temperature sodium–sulfur(Na–S)batteries are severely hampered by dissolution of polysulfides into electrolytes.Herein,a facile approach is used to tune a biomass-derived carbon down to an ultrasmall 0.37 nm mi...Room temperature sodium–sulfur(Na–S)batteries are severely hampered by dissolution of polysulfides into electrolytes.Herein,a facile approach is used to tune a biomass-derived carbon down to an ultrasmall 0.37 nm microporous structure for the first time as a cathode in sodium–sulfur batteries.This produced an intact uniform Na2S membrane to greatly confine the dissolution of polysulfides while realizing a direct solid phase conversion for complete reduction of sulfur to Na2S,which delivers a sulfur loading of 1 mg cm−2(50 wt.%),an excellent rate capacity(933 mAh g^(−1)@0.1 A g^(−1)and 410 mAh g^(−1)@2Ag^(−1)),long cycle performance(0.036%per cycle decay at 1 A g^(−1)after 1500 cycles),and a high energy density for 373 Wh kg^(−1)(0.1 A g^(−1))based on whole electrode weight(active sulfur loading+carbon),ranking the best among all reported plain carbon cathode-based room temperature sodium–sulfur batteries in terms of the cycle life and rate capacity.It is proposed that the solid Na2S produced in the ultrasmall pores(0.37 nm)can be squeezed out to grow an intact membrane on the electrode surface covering the outlet of the pores and greatly depressing the dissolution effect of polysulfides for the long cycle life.This work provides a green chemistry to recycle wastes for sustainable energies and sheds light on design of a unique pore structure to effectively block the dissolution of polysulfides for high-performance sodium–sulfur batteries.展开更多
采用碳酸盐共沉淀的方法成功制备了不同二次颗粒粒径的富锂层状正极材料Li1.2Mn0.54Ni0.13Co0.13O2。并运用X射线衍射(XRD)、场发射扫描电镜(FESEM)、激光粒度测试和电化学测试等手段对所得材料的结构、形貌、粒度分布及电化学性能进行...采用碳酸盐共沉淀的方法成功制备了不同二次颗粒粒径的富锂层状正极材料Li1.2Mn0.54Ni0.13Co0.13O2。并运用X射线衍射(XRD)、场发射扫描电镜(FESEM)、激光粒度测试和电化学测试等手段对所得材料的结构、形貌、粒度分布及电化学性能进行表征。结果显示,不同二次颗粒粒径的Li1.2Mn0.54Ni0.13Co0.13O2在材料结构上没有明显的差别,且首次放电比容量接近,均达到了281m Ah·g-1。但是,二次颗粒粒径越小,富锂层状材料的表现出的倍率性能越优异,当二次颗粒的D50为4.59μm,其在3C倍率下的放电容量达到了199 m Ah·g-1。这是因为二次颗粒粒径越小,富锂层状材料可更好的与导电剂和电解液接触,且锂离子的扩散路径更短,从而表现出更好的倍率特性。展开更多
熔融碳酸盐燃料电池(MCFC)发电技术是一种清洁高效的新型发电技术,成本较高一直是制约其发展的重要因素。本文围绕电池堆成本问题,研究开发了一种新型改性阴极,将电池性能提升了2.6倍,这将减少同功率水平电池堆关键部件用量,降低了电池...熔融碳酸盐燃料电池(MCFC)发电技术是一种清洁高效的新型发电技术,成本较高一直是制约其发展的重要因素。本文围绕电池堆成本问题,研究开发了一种新型改性阴极,将电池性能提升了2.6倍,这将减少同功率水平电池堆关键部件用量,降低了电池堆成本。实验结果表明,在0.7 V放电条件下,采用改性阴极的电池功率密度达到了130 m W/cm^2,而采用原阴极的电池同条件下功率密度为50 m W/cm^2。该新型改性阴极的成功研出有助于大功率低成本的MCFC电池堆开发。展开更多
基金This work was supported by the National Nature Science Foundation of China(NSFC)(Nos.20921001 and 90606006)the Tsinghua University Initiative Scientific Research Program(No.2009HTZ08).
文摘Solid and hollow microspheres of LiMn_(2)O_(4) have been synthesized by lithiating MnCO_(3) solid microspheres and MnO_(2) hollow microspheres,respectively.The LiMn_(2)O_(4) solid microspheres and hollow microspheres had a similar size of about 1.5μm,and the shell thickness of the hollow microspheres was only 100 nm.When used as a cathode material in lithium ion batteries,the hollow microspheres exhibited better rate capability than the solid microspheres.However,the tap density of the LiMn_(2)O_(4) solid microspheres(1.0 g/cm^(3))was about four times that of the hollow microspheres(0.27 g/cm^(3)).The results show that controlling the particle size of LiMn_(2)O_(4) is very important in terms of its practical application as a cathode material,and LiMn_(2)O_(4) with moderate particle size may afford acceptable values of both rate capability and tap density.
基金financial support from Chongqing Postdoctoral Natural Science Foundation No.cstc2020jcyj-bsh0048State Key Laboratory of Silkworm Genome Biology,Suzhou Foreign Academician Workstation(SWY2021002)Collaborative Innovation Center of Water Treatment Technology and Material,and Innovation Platform for Academicians of Hainan Province
文摘Room temperature sodium–sulfur(Na–S)batteries are severely hampered by dissolution of polysulfides into electrolytes.Herein,a facile approach is used to tune a biomass-derived carbon down to an ultrasmall 0.37 nm microporous structure for the first time as a cathode in sodium–sulfur batteries.This produced an intact uniform Na2S membrane to greatly confine the dissolution of polysulfides while realizing a direct solid phase conversion for complete reduction of sulfur to Na2S,which delivers a sulfur loading of 1 mg cm−2(50 wt.%),an excellent rate capacity(933 mAh g^(−1)@0.1 A g^(−1)and 410 mAh g^(−1)@2Ag^(−1)),long cycle performance(0.036%per cycle decay at 1 A g^(−1)after 1500 cycles),and a high energy density for 373 Wh kg^(−1)(0.1 A g^(−1))based on whole electrode weight(active sulfur loading+carbon),ranking the best among all reported plain carbon cathode-based room temperature sodium–sulfur batteries in terms of the cycle life and rate capacity.It is proposed that the solid Na2S produced in the ultrasmall pores(0.37 nm)can be squeezed out to grow an intact membrane on the electrode surface covering the outlet of the pores and greatly depressing the dissolution effect of polysulfides for the long cycle life.This work provides a green chemistry to recycle wastes for sustainable energies and sheds light on design of a unique pore structure to effectively block the dissolution of polysulfides for high-performance sodium–sulfur batteries.
文摘采用碳酸盐共沉淀的方法成功制备了不同二次颗粒粒径的富锂层状正极材料Li1.2Mn0.54Ni0.13Co0.13O2。并运用X射线衍射(XRD)、场发射扫描电镜(FESEM)、激光粒度测试和电化学测试等手段对所得材料的结构、形貌、粒度分布及电化学性能进行表征。结果显示,不同二次颗粒粒径的Li1.2Mn0.54Ni0.13Co0.13O2在材料结构上没有明显的差别,且首次放电比容量接近,均达到了281m Ah·g-1。但是,二次颗粒粒径越小,富锂层状材料的表现出的倍率性能越优异,当二次颗粒的D50为4.59μm,其在3C倍率下的放电容量达到了199 m Ah·g-1。这是因为二次颗粒粒径越小,富锂层状材料可更好的与导电剂和电解液接触,且锂离子的扩散路径更短,从而表现出更好的倍率特性。
文摘熔融碳酸盐燃料电池(MCFC)发电技术是一种清洁高效的新型发电技术,成本较高一直是制约其发展的重要因素。本文围绕电池堆成本问题,研究开发了一种新型改性阴极,将电池性能提升了2.6倍,这将减少同功率水平电池堆关键部件用量,降低了电池堆成本。实验结果表明,在0.7 V放电条件下,采用改性阴极的电池功率密度达到了130 m W/cm^2,而采用原阴极的电池同条件下功率密度为50 m W/cm^2。该新型改性阴极的成功研出有助于大功率低成本的MCFC电池堆开发。
