Cellulose sulfate lithium as a conductive binder for LiFePO4 cathode with long cycle life.

Polysaccharides can be potential binders for lithium-ion batteries due to their strong adhesion through numerous hydroxyl groups. As a novel waterborne lithiated polysaccharide derivative, cellulose sulfate lithium (CSL) is successfully synthesized and used as the binder for LiFePO4 (LFP) cathode. The chemical structure of CSL is verified by FTIR-ATR, XRD, C13-NMR, GPC, EA, ICP and TGA. Compared to LFP cathode using polyvinylidene difluoride binder, electrochemical measurements show that the LFP cathode using CSL (LFP-CSL) has lower polarization and better rate performance owing to higher lithium-ion conductivity of CSL. The result of morphological analysis indicates that CSL binder can maintain an integrated LFP cathode structure during hundreds of cycles. As a result, the LFP-CSL cathode exhibits a discharge capacity of 133.4 mAh g-1 and maintains remarkable cycle stability with retention of 93.1 % after 300 cycles at 1C. These findings provide novel insights into the rational design of the binders for the LFP cathode.

Core-shell (nano-SnX/nano-Li4Ti5O12)@C spheres (X = Se,Te) with high volumetric capacity and excellent cycle stability for lithium-ion batteries.

Among binary tin chalcogenides as anode materials for lithium-ion batteries, SnSe and SnTe have attracted attention due to their high theoretical volumetric capacity. However, they suffer from sluggish dynamics and serious agglomeration during lithiation/delithiation processes, which leads to inferior cycling performance. This study reports core-shell structure (nano-SnSe/nano-Li4Ti5O12)@C and (nano-SnTe/nano-Li4Ti5O12)@C [denoted as (n-SnX/n-LTO)@C] with extraordinary lithium storage stability. Benefiting from the well-designed structural merits, the core-shell structure of (n-SnX/n-LTO)@C is well preserved over 500 cycles, suggesting its high structural integrity. The (n-SnSe/n-LTO)@C and (n-SnTe/n-LTO)@C anodes deliver high initial volumetric capacities of 3470.1 and 3885.4 mA h cm-3 at 0.2 A g-1 and maintain capacities of 2066.0 and 1975.3 mA h cm-3 even after 500 cycles, respectively. This work provides a new avenue for designing novel binary tin chalcogenide lithium-ion battery anodes with high volumetric capacity and superior long-term cycling performance.

One-step hydrothermal synthesis of Cu-doped MnO2 coated diatomite for degradation of methylene blue in Fenton-like system.

In this work, we have synthesized Cu-doped MnO2@diatomite successfully though a one-step hydrothermal approach. Meanwhile, application for degradation of methylene blue in Fenton-like system was investigated. The compounds were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), Inductively Coupled Plasma analysis (ICP) and UV-vis spectroscopy measurements, beam scanning electron microscope (FIB/SEM), energy dispersive X-ray spectrometer (EDS). The observations revealed that copper was indeed intercalated into layered structure of MnO2 and Density functional theory (DFT) calculations predicted that Cu2+ intercalated MnO2@diatomite brought about the narrowing of band gap and the enhancing of charge mobility during catalysis. Electron Density Difference of CuMnD demonstrated excellent oxidation ability to dissociate H2O2 and generate hydroxyl radical (OH) to degrade the MB. Moreover, the proper copper doping of sample is more easily to form oxygen defect, which generate more surface hydroxyl groups as reaction sites for surface adsorption. In addition, the degradation efficiency of CuMnD was tremendously influenced by the initial pH, H2O2 dosage and copper content of catalyst. Ultimately, 0.02-25-CuMnD along with molar ration of Cu/Mn with 0.4402 showed the best degradation efficiency which was about 96.2% within 4 h with 16.5 mM of H2O2 and pH 2.06.

Kinetic analysis of one-step solid-state reaction for Li4Ti5O12/C.

The kinetics of one-step solid-state reaction of Li(4)Ti(5)O(12)/C in a dynamic nitrogen atmosphere was first studied by means of thermogravimetric-differential thermal analysis technique at five different heating rates. According to the double equal-double steps method, the Li(4)Ti(5)O(12)/C solid-state reaction mechanism could be properly described as the Jander equation, which was a three-dimensional diffusion with spherical symmetry, and the reaction mechanism functions were listed as follows: f(α) = (3)/(2)(1 - α)(2/3)[1 - (1 - α)(1/3)](-1), G(α) = [1 - (1 - α)(1/3)](2). In FWO method, average activation energy, frequency factor, and reaction order were 284.40 kJ mol(-1), 2.51 × 10(18) min(-1), and 1.01, respectively. However, the corresponding values in FRL method were 271.70 kJ mol(-1), 1.00 × 10(17) min(-1), and 0.96, respectively. Moreover, the values of enthalpy of activation, Gibbs free energy of activation, and entropy of activation at the peak temperature were 272.06 kJ mol(-1), 240.16 kJ mol(-1), and 44.24 J mol(-1) K(-1), respectively.