Zhang Yifang, Su Qiong, Xu Wenjie, Cao Guozhong, Wang Yaping, Pan Anqiang, Liang Shuquan
Department of Materials Physics and Chemistry School of Materials Science and Engineering Central South University Changsha Hunan 410083 China.
Department of Chemistry and Energy Sciences Institute Yale University West Haven CT 06516 USA.
Adv Sci (Weinh). 2019 Jun 17;6(16):1900162. doi: 10.1002/advs.201900162. eCollection 2019 Aug 21.
The inferior tolerance with reversible accommodation of large-sized Na ion in electrode materials has plagued the adaptability of sodium-ion chemistry. The sluggish diffusion kinetics of Na also baffles the desirability. Herein, a carbon fiber supported binder-free electrode consisting of bismuth and carbon composite is designed. Well-confined bismuth nanodots are synthesized by replacing cobalt in the metal-organic frameworks (MOF)-derived, nitrogen-doped carbon arrays, which are demonstrated with remarkable reversibility during sodiation and desodiation. Cobalt species in the pristine MOF catalyze the graphitization around organic components in calcination, generating a highly conductive network in which the bismuth is to be embedded. The uniformly dispersed bismuth nanodots provide plenty boundaries and abundant active sites in the carbon arrays, where fast sodium storage kinetics are realized to contribute extra capacity and excellent rate performance.
电极材料中对大尺寸钠离子的可逆容纳能力较差，这一直困扰着钠离子化学的适应性。钠离子缓慢的扩散动力学也阻碍了其发展。在此，设计了一种由铋和碳复合材料组成的碳纤维支撑无粘结剂电极。通过在金属有机框架（MOF）衍生的氮掺杂碳阵列中取代钴，合成了封装良好的铋纳米点，在钠化和脱钠过程中表现出显著的可逆性。原始MOF中的钴物种在煅烧过程中催化有机成分周围的石墨化，形成一个高导电网络，铋将嵌入其中。均匀分散的铋纳米点在碳阵列中提供了大量的边界和丰富的活性位点，实现了快速的钠存储动力学，有助于提供额外的容量和优异的倍率性能。
