Facile Ion-Exchange Strategy for Na+/K+ Hybrid-Ion Batteries with Superior Rate Capability and Cycling Performance,ACS Applied Energy Materials

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Facile Ion-Exchange Strategy for Na+/K+ Hybrid-Ion Batteries with Superior Rate Capability and Cycling Performance
ACS Applied Energy Materials ( IF 5.4 ) Pub Date : 2020-06-18 00:00:00 , DOI: 10.1021/acsaem.0c01060
Kyungsoo Shin _{1,

2} , Yongping Zheng ₁ , Fan Zhang _{1,

2} , Shi Wu ₁ , Yongbing Tang _{1,

2}

Affiliation

Potassium-ion batteries (KIBs) have recently attracted growing attention as next-generation energy storage devices; however, their development is hindered by the poor rate and cycling performance because of the sluggish K⁺ diffusion kinetics. In this work, we first design a Na⁺/K⁺ hybridization strategy by a facile ion-exchange using a 4A molecular sieve as both an ion exchanger and dehydrant to greatly enhance the electrochemical performances of the KIB. By adjusting the adding amount of the 4A molecular sieve, the Na⁺ content in the electrolyte can be controlled, and 25 wt % 4A molecular sieve addition is found to be the optimized condition with the best electrochemical performance. Consequently, we successfully construct a full-cell configuration Na⁺/K⁺ hybrid-ion battery (NKHIB) based on the Na⁺/K⁺ hybrid-ion electrolyte with Sn foil as the anode and graphite as the cathode, which achieves excellent electrochemical performances including superior rate capability with 74% capacity retention up to 30 C and long cycle life with negligible capacity decay over 500 cycles, among the best values of the reported KIBs. Ex situ characterizations demonstrate that the NaSn alloy starts to form before KSn formation on the Sn anode, and density functional theory calculations further reveal that the presodiation in the Sn structure provides a fast channel for the following K-ion diffusion, thus enhancing the ion-diffusion kinetics in the NKHIB. In addition, this hybridizing strategy also enables the battery to exhibit stable performance in a wide working temperature range from −20 to 55 °C, suggesting its potential application for high-performance and wide-temperature-range energy-storage devices.

中文翻译：

适用于Na ⁺ / K ⁺混合离子电池的便捷离子交换策略，具有出色的速率能力和循环性能

钾离子电池（KIB）作为下一代能量存储设备最近已引起越来越多的关注。然而，由于K ⁺扩散动力学迟缓，它们的发展受到速率和循环性能差的阻碍。在这项工作中，我们首先通过使用4A分子筛作为离子交换剂和脱水剂的便捷离子交换设计Na ⁺ / K ⁺杂交策略，以大大增强KIB的电化学性能。通过调整4A分子筛的加入量，中的Na ⁺可以控制电解质中的含量，并且发现添加25 wt％的4A分子筛是具有最佳电化学性能的最佳条件。因此，我们成功地构建了以Na ⁺ / K ⁺杂化离子电解质为基础，以锡箔为阳极，石墨为阴极的全电池型Na ⁺ / K ⁺杂化离子电池（NKHIB），实现了出色的电化学性能这些性能包括所报告的KIB的最佳值，其中包括卓越的速率性能，高达30％的容量保持74％的容量，以及500次循环中的容量衰减可忽略不计的长循环寿命。异地表征表明，在锡阳极上形成KSn之前，NaSn合金开始形成，并且密度泛函理论计算进一步揭示，Sn结构中的预沉淀为随后的K离子扩散提供了快速通道，从而增强了离子扩散动力学在NKHIB中。此外，这种杂交策略还使电池在-20至55°C的宽工作温度范围内都能表现出稳定的性能，这表明其在高性能和宽温度范围储能设备中的潜在应用。

更新日期：2020-06-18

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