Improved Performance of Nano-Sized Polyoxometalate as Lithium-Battery Cathode by Conductive Polymer Coating

Erfe Ni, Tetsuya Tsukada, Qing Wen, Noriyuki Sonoyama
2018 Journal of the Electrochemical Society  
Polyoxometalates have been investigated for use as high-capacity cathode materials in lithium batteries due to their high capacity, cycle stability, and recoverability of crystal structure during charge-discharge. However, POMs have weak points when used as the cathode electrode for lithium batteries: low electronic conductivity and high surface reactivity. In this study, we used a conducting polymer, polypyrrole (PP), to coat the surface of nano-sized polyoxovanadate K 9 PV 14 O 32 (KPV) and
more » ... amined the electrochemical properties. By optimizing the coating conditions, the PP uniformly covers the surface of KPV nanoparticles, with a thickness of about 5 nm. The capacity of PP-coated KPV increased to 500 mAhg −1 and 90% of its initial capacity was retained after 50 cycles. The capacity at high current density (1000 mAhg −1 ) was also improved from 200 mAhg −1 to 280 mAhg −1 , with 93% capacity retention after 50 cycles. This high capacity and rate performance is due to the improvement in the electronic conductivity of POMs. The PP layer also suppressed the surface reactions in KPV, which improves the cycle stability of the cell.
doi:10.1149/2.0341903jes fatcat:ffipilyzhbbkvc7i55s7z77bmm