Can the Calcined Weathered Stones be Employed as Anode Materials for Lithium Ion Batteries?

A novel finding, that the calcined weathered stones (denoted as CWS) can be employed as the anode materials for lithium ion batteries (LIBs), is reported for the first time in this work. Under the air conditions, the weathered stones were respectively calcined at 400ºC (sample a), 600ºC (sample b) and 800ºC (sample c) for 2 h, with an intention to examine the influence of the calcination temperature on the physicochemical properties of the resultant materials. XRD results indicated that the main components of all the final products were SiO2. And the SEM images demonstrated that all the as-prepared samples were irregular and larger particles with no evident crystal structure. The results of the electrochemical measurements revealed that the initial discharge capacity of sample b was about 104 mAh g-1 at the current density of 100 mA g-1, which was remarkably larger than that of the employed pure SiO2 (50 mAh g-1). Interestingly, after 20 cycles, the discharge capacity of sample b was still maintained as high as 70 mAh g-1, along with a capacity retention rate of about 70%. Although the discharge capacity reported here was lower as compared to the currently reported anode materials, this novel finding was very meaningful to the large scale production of anode materials, mainly due to the rather lower cost and abundant resources as well as the simple preparation process.