Synthesis and Characterization of Alginate-Based Sol–Gel Synthesis of Lithium Nickel Phosphate with Surface Area Control

Abstract

A sol−gel method in which alginate was used to help prepare carbon-coated LiNiPO 4 nanocrystal aggregates with controllable surface area is reported. Nickel alginate prepared from NiCl 2 and sodium alginate was blended with stoichiometric LiOH and H 3 PO 4 to produce a single-source precursor gel. Calcining the gel in air at 400−800 °C produced LiNiPO 4 nanocrystal aggregates with different levels of crystallinity, sizes, and surface areas. Powder X-ray diffraction, fieldemission scanning electron microscopy, high-resolution transmission electron microscopy, and Brunauer−Emmett−Teller analyses collectively showed that 600 °C was the optimal calcination temperature that gave LiNiPO 4 with an average crystallite size of 43 nm, a surface carbon coating of 2−4 nm, and a surface area of 27.47 m 2 /g. The method allows simultaneous achievement of four features, namely, surface carbon coating, high crystallinity, control of primary particle size, and high surface area. Simple modification of the method would allow the production of a wider range of LiMPO 4 (M = Fe, Co, Mn).

Electrochemical Performance of Carbon Modified LiNiPO4 as Li-Ion Battery Cathode: A Combined Experimental and Theoretical Study

“…DTG thermogram revealed a sharp peak at 163.06 °C indicating rapid decomposition of nickel acetate. 5 A constant weight after 200 °C indicated that no heat is used for evaporation and decomposition processes and that LiNiPO 4 can be obtained by firing the precursor at temperature above 200 °C. Based on thermogravimetric results, three temperatures were selected; 450 °C, 550 °C and 650 °C as point of interest for the production of LiNiPO 4 via calcination of gel precursors.…”

“…3 Unique new and improved cathode materials are continuously being developed to cope with the demanding capacity and stability issues in LIBs. 4,5 In the past few years, extensive studies have been carried out on lithium conducting metal phosphates, LiMPO 4 (M = Ni, Mn, Co, Fe) as promising polyanion cathode materials for lithium ion batteries on account of their inherit merits such as good thermal stability, stable potential plateau, decent electrochemical properties, low cost, envir onment benignity and excellent cycling performance. 6,7 Among these olivine phosphates, LiFePO 4 as cathode material has been researched in detail and is also well optimized for its use in LIBs as cathode material.…”

“…18 It is expected that enhance ment in electronic conductivities can improve charge and discharge performances of LiNiPO 4 cathodes. 5,19 Carbon modification has been proved to be an effective methodology to improve the ionic and electronic conductivities of LIB cathode materials. The presence of carbon can also help to obtain small sized particles via preventing the particle aggregation and grain growth.…”

Alginate-Based Applications in Biotechnology with a Special Mention to Biosensors

“…These metal ions can be prepared for immobilisation by treatment with a chelating moiety such as nitrilotriacetic acid [102,103] or iminodiacetic acid and can be used alone. For example, because alginate is polyanionic, several alginate nickel composites have been prepared from alginate and NiCl 2 [104,105]. Other affinity tags such as biotin and avidin can be attached to the biomolecules by selected chemistries [106].…”

2018 International Conference of Chemical Engineering and Industrial Biotechnology (ICCEIB) Preface

“…Kim et al 12 developed an energy-efficiency recycling technique operable under various reactive gases and pyrolysis time and applied it on a polymer matrix decomposition study. Thong et al 13 report on the use of a sol−gel method in which alginate was used to help prepare a carbon-coated LiNiPO 4 nanocrystal aggregate with controllable surface area. They reported an average crystallite size of 43 nm, a surface carbon coating of 2− 3 nm, and a surface area of 27.47 m 2 /g.…”