Achieving ultralong life sodium storage in amorphous cobalt-tin binary sulfide nanoboxes sheathed in N-doped carbonElectronic supplementary information (ESI) available: TGA, Raman, XRD spectra and more SEM, TEM data, as well as additional electrochemical spectra. See DOI: 10.1039/c7ta01701d

• Main Authors: Liu, Xu, Wang, Yuwei, Wang, Zhiyu, Zhou, Tao, Yu, Mengzhou, Xiu, Luyang, Qiu, Jieshan
• Format: Journal Article
• Language: English
• Published: 30.05.2017
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c7ta01701d

The interest in Na-ion batteries (NIBs) is growing exponentially since Na is more abundant and affordable than Li for large-scale energy storage applications. However, the lack of truly durable and high-capacity electrode materials still remains a key bottle-neck issue for the development of practical NIBs. In this work, we report the rational design of an ultra-long life anode material for NIBs by integrating the structural merits of hollow nanostructures, carbon nanocoating and amorphous structures together into a binary metal sulfide system. Amorphous CoSnS x nanoboxes sheathed in N-doped carbon are yielded by templating against single-crystalline CoSn(OH) 6 nanoboxes, followed by polymer nanoplating and carbonization. The synergy of diverse structural features enables a robust structure and fast reaction kinetics for Na storage in the CoSnS x @NC anode, leading to an exceptionally long cycle life of 4000 cycles with very slow capacity loss (0.0075% per cycle) and high power output. The full cells assembled from the Na 3 V 2 (PO 4 ) 3 /C cathode and the CoSnS x @NC anode deliver a high energy density of up to 86.6 W h kg −1 , as well as good capacity retention at high current rate. Amorphous CoSnS x nanoboxes sheathed in N-doped carbon (CoSnS x @NC) are fabricated as ultra-long life anode materials in Na-ion batteries.