Birnessite Nanosheet Arrays with High K Content as a High-Capacity and Ultrastable Cathode for K-Ion Batteries
Birnessite Nanosheet Arrays with High K Content as a High-Capacity and Ultrastable Cathode for K-Ion Batteries
复制标题
具有高 K 含量的水钠锰矿纳米片阵列作为 K 离子电池的高容量和超稳定阴极
DOI：
10.1002/adma.201900060
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发表时间：
2019-06-01
影响因子：
29.4
通讯作者：
Xia, Hui
中科院分区：
文献类型：
--
作者：
Lin, Baowei;Zhu, Xiaohui;Xia, Hui
钾离子电池（PIB）是新兴的储能技术之一，因为钾的成本低，理论上能量密度高。然而，PIBs的发展受到K+输运动力学差和在K+嵌入/脱嵌期间阴极材料的结构不稳定性的阻碍。在这项工作中，具有高K含量的水钠锰矿纳米片阵列（K0.77MnO2.0.23H（2）O）作为PIB的潜在阴极，在100 mA g（-1）的电流密度下表现出约134 mAh g（-1）的可逆比容量，以及高倍率容量（1000 mA g（-1）下为77 mAh g（-1））和上级的循环稳定性（1000 mA g（-1）下1000次循环后容量保持率为80.5%）。通过在层间引入足够的K+离子，K-水钠锰矿表现出高度稳定的层状结构，在K+嵌入/脱嵌时具有高度可逆的结构变化。通过构建具有硬-软复合碳阳极的全电池，进一步证明了K-水钠锰矿阴极在PIB中的实际可行性。这项研究强调了水钠锰矿的有效K+嵌入，以实现PIB的上级K存储性能，使其成为开发锂离子电池以外的可充电电池中的高性能阴极的一般策略。
Potassium-ion batteries (PIBs) are one of the emerging energy-storage technologies due to the low cost of potassium and theoretically high energy density. However, the development of PIBs is hindered by the poor K+ transport kinetics and the structural instability of the cathode materials during K+ intercalation/deintercalation. In this work, birnessite nanosheet arrays with high K content (K0.77MnO2.0.23H(2)O) are prepared by hydrothermal potassiation as a potential cathode for PIBs, demonstrating ultrahigh reversible specific capacity of about 134 mAh g(-1) at a current density of 100 mA g(-1), as well as great rate capability (77 mAh g(-1) at 1000 mA g(-1)) and superior cycling stability (80.5% capacity retention after 1000 cycles at 1000 mA g(-1)). With the introduction of adequate K+ ions in the interlayer, the K-birnessite exhibits highly stabilized layered structure with highly reversible structure variation upon K+ intercalation/deintercalation. The practical feasibility of the K-birnessite cathode in PIBs is further demonstrated by constructing full cells with a hard-soft composite carbon anode. This study highlights effective K+-intercalation for birnessite to achieve superior K-storage performance for PIBs, making it a general strategy for developing high-performance cathodes in rechargeable batteries beyond lithium-ion batteries.