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SnO2 Quantum Dots: Rational Design to Achieve Highly Reversible Conversion Reaction and Stable Capacities for Lithium and Sodium Storage.
Small ( IF 13.0 ) Pub Date : 2020-06-04 , DOI: 10.1002/smll.202000681
Yong Cheng 1, 2 , Shaohua Wang 1 , Lin Zhou 1 , Limin Chang 2 , Wanqiang Liu 3 , Dongming Yin 1 , Zheng Yi 1 , Limin Wang 1
Affiliation  

SnO2 has been considered as a promising anode material for lithium‐ion batteries (LIBs) and sodium ion batteries (SIBs), but challenging as well for the low‐reversible conversion reaction and coulombic efficiency. To address these issues, herein, SnO2 quantum dots (≈5 nm) embedded in porous N‐doped carbon matrix (SnO2/NC) are developed via a hydrothermal step combined with a self‐polymerization process at room temperature. The ultrasmall size in quantum dots can greatly shorten the ion diffusion distance and lower the internal strain, improving the conversion reaction efficiency and coulombic efficiency. The rich mesopores/micropores and highly conductive N‐doped carbon matrix can further enhance the overall conductivity and buffer effect of the composite. As a result, the optimized SnO2/NC‐2 composite for LIBs exhibits a high coulombic efficiency of 72.9%, a high discharge capacity of 1255.2 mAh g−1 at 0.1 A g−1 after 100 cycles and a long life‐span with a capacity of 753 mAh g−1 after 1500 cycles at 1 A g−1. The SnO2/NC‐2 composite also displays excellent performance for SIBs, delivering a superior discharge capacity of 212.6 mAh g−1 at 1 A g−1 after 3000 cycles. These excellent results can be of visible significance for the size effect of the uniform quantum dots.

中文翻译:

SnO2量子点:实现高度可逆的转化反应和稳定的锂和钠储存容量的合理设计。

SnO 2被认为是锂离子电池(LIB)和钠离子电池(SIB)的有希望的负极材料,但对于低可逆转化反应和库仑效率也具有挑战性。为了解决这些问题,本文将SnO 2量子点(≈5nm)嵌入多孔的N掺杂碳基质(SnO 2/ NC)是通过在室温下将水热步骤与自聚合过程相结合而开发的。量子点中的超小尺寸可以大大缩短离子扩散距离并降低内部应变,从而提高转化反应效率和库仑效率。丰富的中孔/微孔和高导电性的N掺杂碳基体可以进一步增强复合材料的整体导电性和缓冲作用。结果,针对锂离子电池的优化SnO 2 / NC-2复合材料表现出72.9%的高库仑效率,100次循环后在0.1 A g -1下的高放电容量1255.2 mAh g -1以及的容量的753毫安克-1 1 A G 1500次循环之后-1。锡2 / NC-2复合材料还对SIB表现出出色的性能,经过3000次循环后,在1 A g -1下具有212.6 mAh g -1的出色放电容量。这些优异的结果对于均匀量子点的尺寸效应可能具有明显的意义。
更新日期:2020-07-02
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