Nanocrystalline porous α-LiFeO₂–C composite—an environmentally friendly cathode for the lithium-ion battery

Abstract

A novel nanocrystalline porous a-LiFeO 2 -C composite with a high surface area of around 115 m 2 g À1 has been synthesized by a simple molten salt method, followed by a carbon coating process. The structure and morphology were confirmed by X-ray diffraction, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). FE-SEM observations demonstrated that the morphology consists of a-LiFeO 2 -C nanoclusters composed of very tiny nanoparticles joined together by a porous architecture. TEM investigations revealed that amorphous carbon was incorporated into the pores among the nanoparticles and that some nanoparticles were covered by a thin layer of carbon as well. Electrochemical measurements showed that the a-LiFeO 2 -C nanocomposite delivered a significantly higher reversible capacity and excellent cycle stability (230 mA h g À1 at 0.5 C after 100 cycles). Even at the high rate of 3 C, the electrode showed more than 50% of the capacity at low rate (0.1 C). The excellent electrochemical performance of the a-LiFeO 2 -C nanocomposite electrode can be attributed to the porous conductive architecture among the nanoparticles, which not only has benefits in terms of decreasing the absolute volume changes and increasing the mobility of lithium ions, but also offers conductive pathways along the whole interconnected wall in the structure, which is favourable for the transport of electrons, promotes liquid electrolyte diffusion into the bulk materials, and acts as a buffer zone to absorb the volume changes.

Hydrothermal Stripping Synthesis of α-LiFeO2Nanoparticles from Qinghai Salt Lake Brine

“…Each diffraction peak in Fig. 2b could be clearly ascribed to Į-LiFeO 2 (cubic rock salt structure, Space Group: Fm3m, a = 4.158 Å) [12] , quite consistent with the JCPDS 17-0938 and the XRD spectrum of Į-LiFeO 2 prepared in other methods [5][6][7][8][9][10][11][12][13][14] . The sharp and narrow peaks indicate good crystallinity of the sample.…”

“…The synthesis of Į-LiFeO 2 was explored extensively in the past 20 years. Now, Į-LiFeO 2 can be synthesized with various methods, such as ionic exchange method [5,6] , molten salt method [3,[7][8][9] , solid phase method [10,11] , hydrothermal method [12,13] , ethanol-thermal method [14] , etc. However, some of the synthesis In this method, Li( ) and Fe( ) which originally exit in water phase attached to organic phase in the extraction process firstly.…”

All-polymer battery system based on polypyrrole (PPy)/para (toluene sulfonic acid) (pTS) and polypyrrole (PPy)/indigo carmine (IC) free standing films

“…Thus, achieving the goals of non-or less toxic and more environmentally friendly materials as electrodes for energy storage devices has become mandatory if clean renewable technologies are to be developed for the future [1][2][3]. In this respect, the concept of all-polymer based batteries and supercapacitors, which was introduced almost three decades ago [4], has recently gained a renewed interest mainly due to the possibilities of manufacturing flexible and safe energy storage devices.…”

K0.25Mn2O4nanofiber microclusters as high power cathode materials for rechargeable lithium batteries

“…26-30 50 On the other hand, nanosized materials and porous materials have larger surface-to-volume ratios that enhance the contact between the active material grains and the electrolyte, and shorten the ion diffusion pathways. 31 It could be deduced that a cathode material with nanosize porous structure and alkaline or alkaline-earth 55 element doping would show improved electrochemical performance.…”