Metal carbonates as anode materials for lithium ion batteries

Six metal carbonates (Li2CO3, Na2CO3, SrCO3, BaCO3, K2CO3, CoCO3) are tested and compared as anode materials for lithium ion batteries. The electrochemical results show that only CoCO3 is electrochemically active material and can deliver a high initial capacity of 1425.9 mAh g(-1). The lithium storage mechanism in CoCO3 is studied by ex situ X-ray diffraction technique, ex situ infrared method, ex situ X-ray photoelectron spectroscopy and in situ X-ray diffraction technique. It is found that the electrochemical reactions between CoCO3 and Li firstly result in the formation of metal Co and Li2CO3, and then partial Li2CO3 is further reduced into carbon (C-0), low-valence carbon (C2+), and Li2O. It also demonstrates that the electrochemical reaction between CoCO3 and Li is a partially reversible process. Based on these electrochemical results, it is obvious that narrow potential range can acquire a better reversibility for CoCO3/Li batteries by suppressing particle pulverization. Besides, the comparison of CoCO3, ball-milled CoCO3 and ball-milled CoCO3/C composite also indicates that smaller active particle and carbon buffer are beneficial to obtain better cycling performance and higher reversible capacity. (C) 2013 Elsevier B.V. All rights reserved.