Sulfur-nitrogen rich carbon as stable high capacity potassium ion battery anode: Performance and storage mechanisms
Sulfur-nitrogen rich carbon as stable high capacity potassium ion battery anode: Performance and storage mechanisms
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DOI：
10.1016/j.ensm.2020.02.004
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发表时间：
2020-05-01
影响因子：
20.4
通讯作者：
Mitlin, David
中科院分区：
文献类型：
--
作者：
Tao, Lin;Yang, Yunpeng;Mitlin, David
合成了用于钾离子阳极的富硫氮结合碳(S=12.9at.%，N=9.9at.%)。低比表面积碳(56m(2)g(-1))的硫与结构共价键合，游离硫最少。这使其具有出色的倍率能力和稳定性：0.1、1和10Ag(-1)时的容量分别为437、234和72mAhg(-1)，3000次循环后在2Ag(-1)时的保持率为75%。这些都是钾离子电池碳文献中报道的最有利的容量-循环性组合。作为原理证明，碳被集成到具有最先进能量和功率的钾离子电容器中(例如，在244W kg(-1)时为110 W h kg(-1))。根据XPS分析，氮与Kthorn的反应不同于Kthorn与硫的反应。N和N-O部分经历了一系列复杂的多电压反应，导致它们的结构发生可逆和不可逆的变化。K-S反应涉及硫化物、硫代硫酸盐和硫酸盐的可逆吸附和可逆生成的组合。GITT和EIS分析表明，在富N碳中掺入S使Kthorn固相扩散系数增加了-3到8倍，具体取决于电压。扩散系数是不对称的，充放电，表明不同的反应路径。在循环初期和长循环阶段，共价结合硫对固体电解质界面的形成也有积极的影响。
Combined sulfur and nitrogen (S = 12.9 at.%, N = 9.9 at.%) rich carbons are synthesized for potassium ion anode applications. The low-surface-area carbons (56 m(2) g(-1)) have sulfur covalently bonded to the structure, with minimum unbound "free" sulfur. This allows for exceptional rate capability and stability: Capacities of 437, 234 and 72 mAh g(-1) are achieved at 0.1, 1 and 10 A g(-1), with 75% retention at 2 A g(-1) after 3000 cycles. These are among the most favorable capacity-cyclability combinations reported in potassium ion battery carbon literature. As a proof of principle, the carbons are incorporated into a potassium ion capacitor with state-of-the-art energy and power (e.g. 110 W h kg(-1) at 244 W kg(-1)). According to XPS analysis, the reaction of nitrogen with Kthorn is distinct from that of Kthorn with sulfur. The N and N-O moieties undergo a series of complex multi-voltage reactions that result in both reversible and irreversible changes to their structure. The K-S reactions involve a combination of reversible adsorption and reversible formation of sulfides, thiosulfate and sulfate. GITT and EIS analysis indicate that incorporation of S into the N-rich carbon increases the Kthorn solid-state diffusion coefficient by factors ranging from -3 to 8, depending on the voltage. The diffusivities are asymmetric with charging vs. discharging, signifying distinct reaction pathways. The covalently bound sulfur also has a positive influence on the solid electrolyte interphase (SEI) formation, at early and at prolonged cycling.