Cobalt carbonate （CoCO3）dumbbells for high-capacity lithium storage: A slight doping of ascorbic acid and an enhancement in electrochemical performances

http://www.sciencedirect.com/science/article/pii/S0378775315004322

doi:10.1016/j.jpowsour.2015.03.016

Shiqiang Zhao, Shanshan Wei, Rui Liu, Yuxi Wang, Yue Yu, Qiang Shen

Journal of Power Sources 284 (2015) 154-161

h i g h l i g h t s

[1] CoCO3 dumbbells are hydrothermally synthesized in the presence of ascorbic acid.
[2] The crystallization and aggregation of CoCO3 are greatly modified by ascorbic acid.
[3] Ascorbic acid doped CoCO3 dumbbells exhibit enhanced electrochemical performances.
[4] The 100th discharge capacity is as high as 1042 mAh g-1 at 200 mA g-1.

g r a p h i c a l a b s t r a c t

a b s t r a c t
Synthesis of materials with desirable nanostructures is a hot research topic owing to their enhanced
performances in contrast to the bulk counterparts. Herein, dumbbell-shaped cobalt carbonate (CoCO3)
nano architectures and the bulk counterpart of CoCO3 rhombohedra are prepared via a facile hydrothermal
route in the presence and absence of ascorbic acid (AA), respectively. By comparison, it has been
found that: the addition of AA in the hydrothermal crystallization system changes the shape of the
building blocks from Co2CO3(OH)2 nanosheets to CoCO3 nanoparticles, and then further influences the
final configuration of the products. When applied as anodes of lithium ion batteries, CoCO3 dumbbells
deliver a 100th capacity of 1042 mAh g1 at 200 mA g1 and even exhibit a long-term value of
824 mAh g1 over 500 cycles at 1000 mA g1, which are much higher than the rhombohedral counterparts
with corresponding 540 and 481 mAh g1 respectively. The much higher capacity, better cycling
stability and enhanced rate performance of CoCO3 dumbbells can be attributed to the higher specific
surface area, smaller charge transport resistance and better structure stability resulting from the slight
doping (~4.6 wt%) of AA, and also relate with a novel lithium storage mechanism in CoCO3.

JPS CoCO3(2015).pdf