Journal of Sol-Gel Science and Technology
ORIGINAL PAPER: SOL-GEL AND HYBRID MATERIALS FOR DIELECTRIC,
ELECTRONIC, MAGNETIC AND FERROELECTRIC APPLICATIONS
Synthesis of LiNiPO
via citrate sol–gel route
Received: 10 February 2018 / Accepted: 15 May 2018
© Springer Science+Business Media, LLC, part of Springer Nature 2018
In this paper, LiNiPO
powders were prepared by sol gel method using citric acid as chelating agent. The article investigated
the effect of annealing temperature and citric acid: Li molar ratio (cit/Li) on the structure and electrochemical properties of
material. The results indicated that pure Pnma LiNiPO
phase was synthesized at 700 and 800 °C. It was found that
the increase of annealing temperature and cit/Li induced rod-to-sphere transition. The particles sizes increased with
increasing annealing temperature, while the particles sizes were increasing ﬁrstly and then decreasing with increasing the
ratio of cit/Li. Decreasing particles sizes had an advantage of both decreasing the charge transfer resistance (Rct) and
improving the reversible capacity of pure olivine LiNiPO
samples. Spherical particles (100–200 nm) prepared at 700 °C
with cit/Li molar ratio of 2:1 were found to have low resistance, high electrochemical reversibility, cycle stability.
The charge transfer resistances (Rct) of LiNiPO
were affected by purity and particles sizes. Owing to the presence of Li
and NiO impurities phase, sample a had high Rct. For other pure LiNiPO
samples, the values of Rct decreased with a
decrease of particles sizes. The purity was the main factor that affected electrical properties (charge transfer resistance and
reversible capacity) of samples, followed by particles sizes.
powders were prepared by citrate sol gel method.
The annealing temperature and citric acid: Li molar ratio (cit/Li) affected the purity, structure and electrochemical
properties of LiNiPO
The increase of annealing temperature improved the purity and particles sizes of samples.
With increasing the ratio of cit/Li, the particles sizes were increasing ﬁrstly and then decreasing.
* Ying Tao
School of Materials Science and Engineering, Central South
University, Changsha, Hunan 410083, China
School of Materials Science and Engineering, Hunan University,
Changsha, Hunan 410082, China