碳中的缺陷选择性和“无序”工程用于持久和快速的钾储存,Advanced Materials

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碳中的缺陷选择性和“无序”工程用于持久和快速的钾储存
Advanced Materials ( IF 29.4 ) Pub Date : 2021-11-30 , DOI: 10.1002/adma.202108621
Yaxin Chen _{1,

2} , Baojuan Xi ₃ , Man Huang ₃ , Liluo Shi ₁ , Shaozhuan Huang ₄ , Nannan Guo ₂ , Da Li ₁ , Zhicheng Ju ₁ , Shenglin Xiong ₃

Affiliation

富含缺陷的碳材料由于活性位点的丰富而具有较高的重量钾存储能力，但由于不良缺陷的低可逆性和劣化的电导率，它们的循环稳定性受到限制。在此，据报道，通过自模板策略在碳中进行原位缺陷选择性和无序协同工程以提高 K ⁺-同时存储容量、倍率容量和循环稳定性。选择性地调整缺陷位点以实现丰富的可逆碳空位，同时通过热解过程中的持续气体释放来牺牲可逆性差的杂原子缺陷。同时，在热解过程中产生的纳米气泡作为自模板诱导表面原子重排，从而将纳米石墨网络原位嵌入缺陷域中而不会产生严重的相分离，从而大大提高了本征导电性。协同结构同时确保高浓度的可逆碳空位和快速的电荷转移动力学，导致高可逆容量（425 mAh g ^-1 at 0.05 A g ^-1）、高倍率（237.4 mAh g ^-1在 1 A g ^-1下）和优异的循环稳定性（在 0.1 A g ^-1下从循环 10 到 400 次的容量保持率为 90.4% ）。这项工作为实现缺陷位点和本征电导率之间的权衡提供了一种合理而简便的策略，并对可逆钾储存机制提供了深刻的见解。

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Defect-Selectivity and “Order-in-Disorder” Engineering in Carbon for Durable and Fast Potassium Storage

Defect-rich carbon materials possess high gravimetric potassium storage capability due to the abundance of active sites, but their cyclic stability is limited because of the low reversibility of undesirable defects and the deteriorative conductivity. Herein, in situ defect-selectivity and order-in-disorder synergetic engineering in carbon via a self-template strategy is reported to boost the K⁺-storage capacity, rate capability and cyclic stability simultaneously. The defect-sites are selectively tuned to realize abundant reversible carbon-vacancies with the sacrifice of poorly reversible heteroatom-defects through the persistent gas release during pyrolysis. Meanwhile, nanobubbles generated during the pyrolysis serve as self-templates to induce the surface atom rearrangement, thus in situ embedding nanographitic networks in the defective domains without serious phase separation, which greatly enhances the intrinsic conductivity. The synergetic structure ensures high concentration of reversible carbon-vacancies and fast charge-transfer kinetics simultaneously, leading to high reversible capacity (425 mAh g⁻¹ at 0.05 A g⁻¹), high-rate (237.4 mAh g⁻¹ at 1 A g⁻¹), and superior cyclic stability (90.4% capacity retention from cycle 10 to 400 at 0.1 A g⁻¹). This work provides a rational and facile strategy to realize the tradeoff between defect-sites and intrinsic conductivity, and gives deep insights into the mechanism of reversible potassium storage.

更新日期：2021-11-30

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