Abstract

The pursuit for batteries with high specific energy provokes the research of high-voltage/capacity cathode materials with superior stability and safety as the alternative for lithium iron phosphate. Herein, using the sol-gel method, a lithium vanadium phosphate with higher average discharge voltage (3.8 V, vs. Li⁺/Li) was obtained from a single source for Mg²+ and Cl⁻ co-substitution and uniform carbon coating, and a nearly theoretical capacity (130.1 mA h g⁻¹) and outstanding rate performance (25 C) are acquired together with splendid capacity retention (80%) after 650 cycles. This work reveals that the well-sized anion and cation substitution and uniform carbon coating are of both importance to accelerate kinetic performance in the context of nearly undisturbed crystal structure for other analogue materials. It is anticipated that the electrochemistry comprehension will shed light on preparing cathode materials with high energy density in the future.

中文翻译：

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通过阴离子和阳离子共取代提高磷酸钒锂的容量

摘要

对高比能量电池的追求激发了对具有高稳定性和安全性的高压/大容量正极材料作为磷酸铁锂的替代品的研究。在本文中，使用溶胶-凝胶法，锂钒磷酸盐具有较高的平均放电电压（3.8伏，相对于Li ⁺ / Li）的由镁单个源获得的² +和Cl ^-共-取代和均匀的碳涂层，和接近理论容量（130.1 mA hg ^-1650次循环后，可获得出色的速率性能（25 C）和出色的容量保持率（80％）。这项工作表明，在其他类似材料几乎未受破坏的晶体结构的情况下，适当大小的阴离子和阳离子取代以及均匀的碳涂层对于加速动力学性能均至关重要。可以预期，电化学理解将在将来为制备高能量密度的阴极材料提供启示。