Hyperporous Sponge Interconnected by Hierarchical Carbon Nanotubes as a High‐Performance Potassium‐Ion Battery Anode
Hyperporous Sponge Interconnected by Hierarchical Carbon Nanotubes as a High‐Performance Potassium‐Ion Battery Anode
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DOI：
10.1002/adma.201802074
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发表时间：
2018-06
影响因子：
29.4
通讯作者：
Yunsong Wang;Zhipeng Wang;Yijun Chen;Hui Zhang;M. Yousaf;Huaisheng Wu;Mingchu Zou;A. Cao
中科院分区：
文献类型：
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作者：
Yunsong Wang;Zhipeng Wang;Yijun Chen;Hui Zhang;M. Yousaf;Huaisheng Wu;Mingchu Zou;A. Cao
最近，商业石墨和其他碳基材料已显示出作为钾离子电池阳极的有前途的性能。与这些碳电极相关的一个基本问题，即显著的体积膨胀和由循环K离子嵌入引起的结构不稳定/塌陷，仍然没有解决，并严重限制了K离子电池的进一步发展和应用。在这里，报道了多壁分级碳纳米管（HCNT）来解决该问题，并且实现了232 mAh g-1的可逆比容量、优异的倍率性能和500次循环的循环稳定性。HCNT的关键结构由具有密集堆叠的石墨壁的内部CNT和具有更多无序壁的松散堆叠的外部CNT组成，并且各个HCNT进一步互连成具有巨大大孔体积、高电导率和可调模量的多孔块状海绵。研究发现，内部致密的CNT作为一个强大的骨架，总的来说，外部松散的CNT有利于K离子的容纳;同时，多孔海绵促进反应动力学，并提供稳定的表面电容行为。碳纳米管的分层结构在开发下一代K和其他金属离子电池的高性能和稳定结构的电极方面具有巨大的潜力。
Recently, commercial graphite and other carbon‐based materials have shown promising properties as the anode for potassium‐ion batteries. A fundamental problem related to those carbon electrodes, significant volume expansion, and structural instability/collapsing caused by cyclic K‐ion intercalation, remains unsolved and severely limits further development and applications of K‐ion batteries. Here, a multiwalled hierarchical carbon nanotube (HCNT) is reported to address the issue, and a reversible specific capacity of 232 mAh g−1, excellent rate capability, and cycling stability for 500 cycles are achieved. The key structure of the HCNTs consists of an inner CNT with dense‐stacked graphitic walls and a loose‐stacked outer CNT with more disordered walls, and individual HCNTs are further interconnected into a hyperporous bulk sponge with huge macropore volume, high conductivity, and tunable modulus. It is discovered that the inner dense‐CNT serves as a robust skeleton, and collectively, the outer loose‐CNT is beneficial for K‐ion accommodation; meanwhile the hyperporous sponge facilitates reaction kinetics and offers stable surface capacitive behavior. The hierarchical carbon nanotube structure has great potential in developing high‐performance and stable‐structure electrodes for next generation K and other metal‐ion batteries.