Insights into the porosity and electrochemical performance of nano Li2FeSiO4 and Li2FeSiO4/C composite cathode materials

ABSTRACT

Nano-Li2FeSiO4/C composites (LFS/C-325 and LFS/C-221) and nano-Li2FeSiO4 (LFS-325 and LFS-221) with controlled porosity were prepared from the nano-fumed silicas with similar particle size and different porosity. N2 adsorption/desorption analysis reveals that the porosity of nano-Li2FeSiO4/C composites and nano-Li2FeSiO4 can be tuned by the choosing nano -fumed silica and LFS/C-325 possess the highest specific surface area among the four samples. XRD indicates that both LFS/C-325 and LFS/C-221 are crystalline powders with monoclinic Li2FeSiO4 of P21. FTIR spectra show that Li-O and Si-O bonds are existed in the four samples. SEM images demonstrate that LFS/C-325 and LFS/C-221 have similar particle sizes in the range of 20 ~ 25 nm, which are distinctly smaller than those of LFS-325 and LFS-221. LFS/C-325 features the smallest particle size and largest specific area, which enables LFS/C-325 to exhibit the best electrochemical performance. The initial discharge capacity of LFS/C-325 is as high as 185.2 mAh g⁻¹ at 0.1 C.

KEYWORDS:

• Li2FeSiO4
• cathode
• lithium ion battery
• nano composite
• electrochemical performance

Disclosure of potential conflicts of interest

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was supported by the National Natural Science Foundation of China [21968016 and 21466020] and the Gansu Provincial Science Fund [No. 1606RJZA180 and 1212RJZA007]