Average particle size and cluster size of metal (M: Cu, Ti)-doped Prussian blue nanoparticles for Li-ion battery anode material

As an anode in Li-ion batteries, cubic or cage forms derived from Prussian blue (PB) analogues have been so attractive although studies are limited for the PB nanoparticle form. In addition, the nanoparticle size affects the electrode performance while such influence on the sono-chemical route mechanism remains largely unexplored in Li-ion batteries. Here, we report a facile co-precipitation method to produce PB nanoparticles, which compare with the addition of sono-chemical route by metal (Cu- and Ti-) doping. The average grain size and fractal dimension of the synthesized PB particles were measured in the range of 18-23 nm and 1.879 +/- 0.009-1.812 +/- 0.016, respectively. By using sono-chemical route assisted co-precipitation, pure and metal-doped PB electrodes reach more than the specific capacity of traditional graphite anodes for 100 cycles. The preferential orientation shifts from (200) to (400) with Ti-doping and improved electrochemical stability with increasing coating ratio. With the decreasing average crystallite size of Cu-doping (18 nm for Debye-Scherrer method), cycle stability also improves. This study presents a new approach by presenting reduced cluster size as well as average particle size of nanoparticles that contribute to the anode performance.