The increasing demand for new energy sources has promoted the improvement of the energy storage capacity of lithium-ion batteries(LIBs)that urged the development of higher energy density cathode materials.The enhancem...The increasing demand for new energy sources has promoted the improvement of the energy storage capacity of lithium-ion batteries(LIBs)that urged the development of higher energy density cathode materials.The enhancement of the classical cathode in the last 30 years has reached a bottleneck,and then the discovery of the lithium-excess disordered materials has greatly expanded the research space of the cathode materials.Compared with the conventional layered oxides,the lithium-excess disordered rock-salt oxides(LEDRXs)with a more stable structure has higher extractable Li^(+)content,even though the inactive high-valent transition metals(TMs)were needed to compensate for the excess Li,which would reduce the total TM redox content.In addition,oxygen redox provides additional electron capacity for the materials,which also causes O loss and results in the subsequent poor cycle performance.Herein,a series of studies about LEDRXs and their targeted modification measures are summarized,including the prospect of the materials,in order to provide ideas for the design of highperformance LEDRXs.Finally,the new discoveries and outlook on future research directions of LEDRX cathode materials for LIBs with higher energy density are given.展开更多
Poor cycling stability,as a long-standing issue,has greatly hindered the commercial application of Li-rich layered oxide cathodes in high-energy-density Li-ion batteries.NiO-type rock-salt phase is commonly considered...Poor cycling stability,as a long-standing issue,has greatly hindered the commercial application of Li-rich layered oxide cathodes in high-energy-density Li-ion batteries.NiO-type rock-salt phase is commonly considered electrochemically inert but stable.Herein,an ultrathin(LixTM1-x)O rock-salt shell was in situ constructed at the particle surface during the synthesis of Li-rich layered oxide cathodes through a unique soft chemical quenching method.Comprehensive structural/chemical analysis reveals that,it not only inherits the chemical stability of traditional NiO-type rock-salt phase,but also facilitates Li^+diffusion due to the co-occupancy of Li^+and TM cations.Such a bifunctional shell could efficiently prevent TM dissolution and oxygen evolution during the long-term cycling,eventually leading to the enhanced cycling stability for Li-rich layered oxides(92.7%of capacity retention after 200 cycles at 0.5 C).It provides new guidance to design and synthesize new Li-rich layered oxides with the excellent cycling stability through utilizing some electrochemically-inert phases.展开更多
川中充西地区多口钻井在雷三2亚段泥灰岩储层中油气显示好,测井解释储层发育,展示了良好的勘探潜力。为准确预测雷三2亚段泥灰岩储层纵横向分布,为下一步勘探部署提供指导,首先利用储层合成记录标定明确储层地球物理响应特征;接着围绕...川中充西地区多口钻井在雷三2亚段泥灰岩储层中油气显示好,测井解释储层发育,展示了良好的勘探潜力。为准确预测雷三2亚段泥灰岩储层纵横向分布,为下一步勘探部署提供指导,首先利用储层合成记录标定明确储层地球物理响应特征;接着围绕岩性和储层分别开展岩石物理分析,优选盐岩和泥灰岩储层的敏感参数,利用地震波形指示模拟预测盐岩的分布;最后利用波形指示反演预测泥灰岩储层的分布。结果表明:雷三2亚段顶部盐岩对应强波峰反射,储层底界对应弱波峰反射,储层与盐岩存在明显的波阻抗重叠,而盐岩与其他岩性在密度上存在明显差异,当去除盐岩的影响后,利用波阻抗可以较好地区分储层和非储层。因此,在利用波形指示模拟识别盐岩分布后,地震波形指示反演可有效识别储层。充西三维区储层大面积发育,厚30~60 m,发育岩性圈闭16个,总面积124 km 2,是下一步富有机质泥灰岩储层的现实勘探方向。展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22179022,22109023 and 22179021)the Industry-University-Research Joint Innovation Project of Fujian Province(No.2021H6006)+3 种基金the Award Program for Fujian Minjiang Scholar Professorshipthe Talent Fund Program of Fujian Normal Universitythe support from the NSERC Discovery Grant(NSERC RGPIN-2020-04463)McGill Start-Up Grant.
文摘The increasing demand for new energy sources has promoted the improvement of the energy storage capacity of lithium-ion batteries(LIBs)that urged the development of higher energy density cathode materials.The enhancement of the classical cathode in the last 30 years has reached a bottleneck,and then the discovery of the lithium-excess disordered materials has greatly expanded the research space of the cathode materials.Compared with the conventional layered oxides,the lithium-excess disordered rock-salt oxides(LEDRXs)with a more stable structure has higher extractable Li^(+)content,even though the inactive high-valent transition metals(TMs)were needed to compensate for the excess Li,which would reduce the total TM redox content.In addition,oxygen redox provides additional electron capacity for the materials,which also causes O loss and results in the subsequent poor cycle performance.Herein,a series of studies about LEDRXs and their targeted modification measures are summarized,including the prospect of the materials,in order to provide ideas for the design of highperformance LEDRXs.Finally,the new discoveries and outlook on future research directions of LEDRX cathode materials for LIBs with higher energy density are given.
基金Supported by National Key R&D Program of China(2016YFB0700600)Soft Science Research Project of Guangdong Province(No.2017B030301013)Shenzhen Science and Technology Research Grant(ZDSYS201707281026184)。
文摘Poor cycling stability,as a long-standing issue,has greatly hindered the commercial application of Li-rich layered oxide cathodes in high-energy-density Li-ion batteries.NiO-type rock-salt phase is commonly considered electrochemically inert but stable.Herein,an ultrathin(LixTM1-x)O rock-salt shell was in situ constructed at the particle surface during the synthesis of Li-rich layered oxide cathodes through a unique soft chemical quenching method.Comprehensive structural/chemical analysis reveals that,it not only inherits the chemical stability of traditional NiO-type rock-salt phase,but also facilitates Li^+diffusion due to the co-occupancy of Li^+and TM cations.Such a bifunctional shell could efficiently prevent TM dissolution and oxygen evolution during the long-term cycling,eventually leading to the enhanced cycling stability for Li-rich layered oxides(92.7%of capacity retention after 200 cycles at 0.5 C).It provides new guidance to design and synthesize new Li-rich layered oxides with the excellent cycling stability through utilizing some electrochemically-inert phases.
文摘川中充西地区多口钻井在雷三2亚段泥灰岩储层中油气显示好,测井解释储层发育,展示了良好的勘探潜力。为准确预测雷三2亚段泥灰岩储层纵横向分布,为下一步勘探部署提供指导,首先利用储层合成记录标定明确储层地球物理响应特征;接着围绕岩性和储层分别开展岩石物理分析,优选盐岩和泥灰岩储层的敏感参数,利用地震波形指示模拟预测盐岩的分布;最后利用波形指示反演预测泥灰岩储层的分布。结果表明:雷三2亚段顶部盐岩对应强波峰反射,储层底界对应弱波峰反射,储层与盐岩存在明显的波阻抗重叠,而盐岩与其他岩性在密度上存在明显差异,当去除盐岩的影响后,利用波阻抗可以较好地区分储层和非储层。因此,在利用波形指示模拟识别盐岩分布后,地震波形指示反演可有效识别储层。充西三维区储层大面积发育,厚30~60 m,发育岩性圈闭16个,总面积124 km 2,是下一步富有机质泥灰岩储层的现实勘探方向。
