Graphenised Lithium Iron Phosphate and Lithium Manganese Silicate Hybrid Cathodes: Potentials for Application in Lithium‐ion Batteries

Abstract

Sol-gel and hand milling techniques were used to prepare a lithium iron phosphate-lithium manganese silicate (LiFePO 4 À Li 2 MnSiO 4) hybrid cathode materials. The structural studies from x-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) show that the materials are well crystallized although few impurities were observed in the pristine LiFePO 4 (LFP) and Li 2 MnSiO 4 (LMS) materials. We used graphene to coat the hybrid cathode materials in order to increase its conductivity and enhance the electrochemical performance. The successful reduction of the graphene oxide into graphene nanosheets was confirmed with the results from the Fourier transform infrared (FTIR) and Raman spectroscopy. The morphological analysis indicate that the pristine materials are made of spherical nanoparticles that are slightly agglomerated while the sol-gel-prepared hybrid cathode materials show evenly distributed spherical nanoparticles with minimal agglomeration. The in situ sol-gel technique gave more homogenously mixed material in comparison to the hand milling method and particle sizes of 37 and 23 nm respectively were obtained for the plain, and graphenised sol gel derived hybrid materials. The sol-gel derived hybrid materials are also the most thermally stable giving a total weight loss of 4.5 % and 3.4 % for the plain and graphenised cathodes respectively. While the LFP-LMS hybrid cathode materials performed better electrochemically more than the pristine materials in terms of enhanced current and specific capacities, the graphenised LFP-LMS hybrid cathode materials showed better electrochemical properties compared to those without graphene. This is associated with the presence of graphene nanosheets in these samples. All the results confirmed that the graphenised LiFePO 4 À Li 2 MnSiO 4 hybrid cathode material prepared via in situ sol-gel method performed better than those of the hand milling method.

Recent Advances in Nonclassical Crystallization: Fundamentals, Applications, and Challenges

“…To date, lithium orthosilicate (Li 2 MSiO 4 with M = Mn, Fe, Co, Ni) has been proven an outstanding mesocrystal candidate for cathode material of Li-ion batteries . With discharge capacity close to its theoretical value, a superior rate capacity, and by being more recyclable for mesocrystalline Li 2 MSiO 4 , there are chances for its application as next-generation high-performance electrode of Li-ion batteries. , The good electrochemical performance makes mesocrystals excellent candidates for sensing applications as well. In sensing formaldehyde and ethanol, polymer-mediated synthesized Co 3 O 4 octahedral mesocrystals showed properties superior to its pure counterparts (Co 3 O 4 powers) .…”

Synergy and Symbiosis Analysis of Capacity-Contributing Polypyrrole and Carbon-Coated Lithium Iron Phosphate Nanostructures for High-Performance Cathode Materials

“…38 group, that in the region from 547 to 650 cm −1 is the intermolecular bending vibration of the [PO 4 ] 3− group, and two small absorption bands at 457 and 502 cm −1 are corresponding to the Li + motion. 39 Obviously, the characteristic peak of PPy is not clearly present in the (C-LFP) 1-x (PPy) x composite, which could be attributed to the relatively few PPy in the composite and the weaker characteristic peak strength of S2), indicating that the residual HCl in PPy was further removed at higher temperatures and…”

“…The characteristic bands of PPy include the CC stretching vibration of the PPy ring at 1550 cm –1 , the C–N stretching mode at 1460 cm –1 , C–H or C–N in-plane deformation modes at 1387 cm –1 , and N–H and C–H stretching vibrations at about 3500 cm –1 . For (C-LFP) 0.93 (PPy) 0.07, (C-LFP) 0.84 (PPy) 0.16, (C-LFP) 0.75 (PPy) 0.25 , (C-LFP) 0.70 (PPy) 0.30 , and C-LiFePO 4 , the spectrum in the region from 965 to 1142 cm –1 is intermolecular stretching vibration modes of the [PO 4 ] 3‑ group, that in the region from 547 to 650 cm –1 is the intermolecular bending vibration of the [PO 4 ] 3– group, and two small absorption bands at 457 and 502 cm –1 are corresponding to the Li + motion . Obviously, the characteristic peak of PPy is not clearly present in the (C-LFP) 1‑x (PPy) x composite, which could be attributed to the relatively few PPy in the composite and the weaker characteristic peak strength of PPy compared with the [PO 4 ] 3– group in LiFePO 4 .…”

Progress and development on the synthesis and application of two-dimensional molybdenum disulphide

“…Due to its high energy density, long lifetime and environmental friendliness, lithium ion batteries (LIBs) and sodium ion batteries (SIBs) have initiated the intensive research on the development of electrode materials. [184][185][186][187][188] Different electronic and nano-microelectronics device such as cell phone and laptops have been using LIBs as energy storage applications. 189,190 In LIBs, graphite is commonly used as anode and lithium metal oxides are used as cathode materials.…”