Hybrid electrolyte based on PEO and ionic liquid with in situ produced and dispersed silica for sustainable solid-state battery

This work introduces the synthesis of hybrid polymer electrolytes based on polyethylene oxide (PEO) and electrolyte solution bis(trifluoromethane)sulfonimide lithium salt/ionic liquid 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide (LiTFSI/EMIMTFSI) with in situ produced and dispersed silica particles by the sol–gel method. Conventional preparation of solid polymer electrolytes was followed by desolvation of lithium salt in a polymer matrix of PEO, which, in some cases, additionally contains plasticizers. This one-pot synthesis is an alternative route for fabricating a solid polymer electrolyte for solid-state batteries. The presence of TFSI- reduces the crystallinity of the PEO matrix (plasticizing effect), increases the dissociation and solubility of LiTFSI in the PEO matrix because of a highly delocalized charge distribution, and reveals excellent thermal, chemical, and electrochemical stability. Tetraethylorthosilicate (TEOS) was chosen due to the slow reaction rate, with the addition of (3-glycidyoxypropyl)trimethoxysilane (GLYMO), which contributes to the formation of a silica network. FTIR studies confirmed the interactions between the silica, the polymer salt, and EMIMTFSI. Impedance spectroscopy measurements were performed in a wide range of temperatures from 25 to 70 °C. The electrochemical performance was explored by assembling electrolytes in LiCoO2 (LCO), NMC(811), and LiFePO4 (LFP) coin half-cells. The HPEf15 shows a discharge capacity of 143 mA/g for NMC(811) at 0.1 C, 134 mA/g for LCO, and 139 mA/g for LFP half-cells at 0.1 C and 55 °C. The LFP half-cell with a discharge capacity of 135 mA/g at 0.1 C (safety potential range of 2.8 to 3.8) obtained a cyclability of 97.5% at 55 °C after 100 cycles. Such a type of electrolyte with high safety and good electrochemical performance provides a potential approach for developing a safer lithium-ion battery.Ministry of Education, Youth, and Sports of the Czech Research, (CZ.005)Ministry of Education, Youth, and Sport of the Czech Researc

Polyaniline/reduced graphene oxide hydrogel film with attached graphite current collector for flexible supercapacitors

Reduced graphene oxide (RGO) hydrogel films possess a low specific capacitance and have no flexible current collectors, which limit their use in flexible supercapacitors. To solve these problems, a novel polyaniline (PANI) modified RGO hydrogel film with an attached graphite current collector (PANI/RGO/G) was prepared. Based on this film, a flexible supercapacitor device was fabricated and characterized. PANI/RGO/G film demonstrates good flexibility and electron transport. The graphite current collector highly reduces the internal resistance of the device. It shows a high specific capacitance of 478 F g−1 at a current density of 2 mA cm−2 based on the mass of one electrode and a good cycling stability (86.5% retention after 5000 cycles). Moreover, during the fabrication of the device, a modified design was adopted to solve the problem of low extension of PANI/RGO/G hydrogel film. The obtained device also exhibits a good flexibility; its capacitance hardly changes after 500 cycles of bending at an angle of 90°. © 2017, Springer Science+Business Media, LLC, part of Springer Nature.LO1504, NPU, Northwestern Polytechnical University; 15520720500, STCSM, Science and Technology Commission of Shanghai Municipality; IGA/CPS/2015/008, ERDF, European Regional Development Fund; CZ.1.05/2.1.00/19.0409, ERDF, European Regional Development Fund; IGA/CPS/2016/003, ERDF, European Regional Development Fund; LTACH17015, MoE, Ministry of Education, Government of the People's Republic of Bangladesh; ERDF, European Regional Development Fund; Research and DevelopmentMinistry of Education, Youth, and Sports of the Czech Republic [LTACH17015]; NPU Program I [LO1504]; Operational Program Research and Development for Innovations - European Regional Development Fund (ERDF); national budget of the Czech Republic within the framework of the CPS-strengthening research capacity [CZ.1.05/2.1.00/19.0409]; Internal Grant Agency from Tomas Bata University in Zlin, Czech Republic [IGA/CPS/2015/008, IGA/CPS/2016/003]; Shanghai Municipality Research Project [15520720500

Enhancing the supercapacitor performance of flexible MnOxCarbon cloth electrodes by Pd-decoration

Manganese oxide (MnOx)-based hybrid electrode materials have been designed by electrochemical deposition on carbon cloth preliminary activated by palladium (Pd) nanoparticles. The synthesis conditions (current density, deposition time) were chosen in such a way as to achieve a stable structure of MnOx with a large surface area. The structural parameters and surface morphology of materials obtained are characterized by Scanning Electron and Transmission Electron Microscopy (SEM, TEM), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), etc. The electrochemical behavior was investigated by cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy. The attained results indicate that MnOx deposits reviled birnessite-type structural feature. Apart from that, the morphology of MnOx transformed with increasing of current density from needlelike structure to loosely-packed thin sheets and then to closed-packed thicker sheets structures. Different morphology exhibits different specific surface area and electrochemical efficiency. Hence electrochemical analysis reviled the highest specific capacitance (186 F g−1) and cyclic stability for MnOxPdCC with obtained at current density of 1 mA cm−2. It can be explained by the formation of a less dense structure of MnOx (loosely-packed thin sheets) with large specific surface area and thus better permeability for Na+ and SO4 −2 ions. As to the role of Pd, its nanoparticles deposited on CC can play a dual role, namely electron conducting passway between CC and MnOx and structure–guiding agent of manganese oxides nucleation and grows. © 2018 Elsevier LtdCZ.1.05/2.1.00/19.0409, CPS, Center for Produce Safety; ERDF, European Regional Development Fund; LO1504, NPU, Northwestern Polytechnical University; LTACH17015, MOE, Ministry of EducationMinistry of Education, Youth, and Sports of the Czech Republic [LTACH17015]; NPU Program I [LO1504]; Operational Program Research and Development for Innovations; European Regional Development Fund (ERDF); national budget of the Czech Republic [CZ.1.05/2.1.00/19.0409