由微孔/中孔组成的多孔工程是通过提供巨大的吸附位点和缩短的离子扩散距离来提高钾储存性能的有效策略。然而,关于大孔在钾储存中的作用的详细探索仍然缺乏,直到现在也几乎没有报道。在这里,以聚单宁酸(PTA)为前体合成了超结构碳六面体(DGN-900)。由于热解过程中PTA沿不同方向和尺寸的空间限制的两步局部收缩,形成有缺陷的具有大孔的纳米片,同时通过调节温度实现缺陷含量和石墨化程度之间的平衡。大孔的存在有利于加速电解质离子在电极内的快速渗透,它的孔体积可以适应循环时电极结构的波动,而最合适的缺陷比石墨提供了丰富的离子吸附位点和足够的电子转移通道,同时。这些优点使DGN-900电极具有突出的电化学性能,包括高倍率(202.9mAhg-1在2Ag-1)和超过2000次循环的长循环稳定性。这种独特的制造策略,也就是说,缺陷工程与大孔结构相结合,使快速和持久的钾储存成为可能。
Multipores engineering composed of micro/mesopores is an effective strategy to improve potassium storage performance via providing enormous adsorption sites and shortened ions diffusion distance. However, a detailed exploration of the role played by macropores in potassium storage is still lacking and has been barely reported until now. Herein, a superstructure carbon hexahedron (DGN-900) is synthesized using poly tannic acid (PTA) as precursor. Due to the spatially confined two-step local contraction of PTA along different directions and dimensions during pyrolysis, defective nanosheets with macropores are formed, while realizing a balance between defects content and graphitization degree by regulating temperature. The presence of macropores is conducive to accelerating electrolyte ions rapid infiltration within electrode, and its pore volume can accommodate electrode structure fluctuation upon cycling, while the most suitable ratio of defects to graphitic provides rich ions adsorption sites and sufficient electrons transfer channels, simultaneously. These advantages enable a prominent electrochemical performance in DGN-900 electrode, including high rate (202.9 mAh g-1 at 2 A g-1 ) and long cycling stability over 2000 cycles. This unique fabrication strategy, that is, defects engineering coupled with macropores structure, makes fast and durable potassium storage possible.