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Understanding the Structure–Performance Relationship of Lithium-Rich Cathode Materials from an Oxygen-Vacancy Perspective
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2020-10-07 , DOI: 10.1021/acsami.0c14979 Shao-Lun Cui 1 , Xu Zhang 1 , Xue-Wen Wu 1 , Sheng Liu 1 , Zhen Zhou 1 , Guo-Ran Li 1 , Xue-Ping Gao 1
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2020-10-07 , DOI: 10.1021/acsami.0c14979 Shao-Lun Cui 1 , Xu Zhang 1 , Xue-Wen Wu 1 , Sheng Liu 1 , Zhen Zhou 1 , Guo-Ran Li 1 , Xue-Ping Gao 1
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Li-rich layered oxide cathode materials are regarded as an attractive candidate of next-generation Li-ion batteries (LIBs) to realize an energy density of >300 Wh kg–1. However, challenges such as capacity fade, cycle life, oxygen release, and structural transformation still restrain its practical application. Micro/nanotechnology is one of the effective strategies to enhance its structural stability and electrochemical performance. An in-depth understanding of the relationship between micro/nanostructures and the electrochemical performance of Li-rich layered oxides is undoubtedly important for developing high-performance cathode materials. Herein, Li1.2Ni0.13Co0.13Mn0.54O2 with different micro/nanostructures including irregular particles, microspheres, microrods, and orthogonal particles are synthesized. Starting from the amount of surface oxygen vacancies in the different structures, the influence of oxygen vacancies on every step during the charge–discharge processes is analyzed by experimental characterizations and theoretical calculations. It is indicated that intrinsic oxygen vacancies can enhance the electrical conductivity and decrease the energy barrier for ion migration, which exerts a significant influence on promoting the kinetics and capacity. Among the different micro/nanostructures, microrods with abundant oxygen vacancies can not only promote lithium ion transport but also stabilize a cathode electrolyte interface (CEI) film by adjusting the distribution of surface elements with lower nickel content. The microrods deliver an initial discharge capacity of up to 306.1 mAh g–1 at 0.1C rate and a superior cycle performance with a capacity retention of 91.0% after 200 cycles at 0.2C rate.
中文翻译：
从氧空位的角度理解富锂阴极材料的结构-性能关系
富锂的分层氧化物阴极材料被视为下一代锂离子电池（LIB）的有吸引力的候选材料，以实现> 300 Wh kg –1的能量密度。然而，诸如容量衰减，循环寿命，氧气释放和结构转变之类的挑战仍然限制了其实际应用。微纳米技术是增强其结构稳定性和电化学性能的有效策略之一。毫无疑问，深入了解微观/纳米结构与富锂层状氧化物的电化学性能之间的关系对于开发高性能阴极材料无疑是重要的。在此，Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2合成了具有不同微/纳米结构的纳米粒子，包括不规则粒子，微球，微棒和正交粒子。从不同结构中表面氧空位的数量出发，通过实验表征和理论计算分析了氧空位对充放电过程中每个步骤的影响。结果表明，固有的氧空位可以提高电导率，降低离子迁移的能垒，对促进动力学和容量产生重要影响。在不同的微/纳米结构中，具有大量氧空位的微棒不仅可以促进锂离子的传输，而且可以通过调节镍含量较低的表面元素的分布来稳定阴极电解质界面（CEI）膜。在0.1C速率下为–1，具有出色的循环性能，在以0.2C速率进行200次循环后，容量保持率为91.0％。
更新日期：2020-10-21
中文翻译：
从氧空位的角度理解富锂阴极材料的结构-性能关系
富锂的分层氧化物阴极材料被视为下一代锂离子电池（LIB）的有吸引力的候选材料，以实现> 300 Wh kg –1的能量密度。然而，诸如容量衰减，循环寿命，氧气释放和结构转变之类的挑战仍然限制了其实际应用。微纳米技术是增强其结构稳定性和电化学性能的有效策略之一。毫无疑问，深入了解微观/纳米结构与富锂层状氧化物的电化学性能之间的关系对于开发高性能阴极材料无疑是重要的。在此，Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2合成了具有不同微/纳米结构的纳米粒子，包括不规则粒子，微球，微棒和正交粒子。从不同结构中表面氧空位的数量出发，通过实验表征和理论计算分析了氧空位对充放电过程中每个步骤的影响。结果表明，固有的氧空位可以提高电导率，降低离子迁移的能垒，对促进动力学和容量产生重要影响。在不同的微/纳米结构中，具有大量氧空位的微棒不仅可以促进锂离子的传输，而且可以通过调节镍含量较低的表面元素的分布来稳定阴极电解质界面（CEI）膜。在0.1C速率下为–1，具有出色的循环性能，在以0.2C速率进行200次循环后，容量保持率为91.0％。
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