A successive preparation of FeCo2O4 nanoflakes arrays on nickel foam substrates is achieved by a simple hydrothermal synthesis method. After 170 cycles, a high capacity of 905 mAh g–1 at 200 mA g–1 ...current density and very good rate capabilities are obtained for lithium-ion battery because of the 2D porous structures of the nanoflakes arrays. The distinctive structural features provide the battery with excellent electrochemical performance. The symmetric supercapacitor on nonaqueous electrolyte demonstrates high specific capacitance of 433 F g–1 at 0.1 A g–1 and 16.7 F g–1 at high scan rate of 5 V s–1 and excellent cyclic performance of 2500 cycles of charge–discharge cycling at 2 A g–1 current density, revealing excellent long-term cyclability of the electrode even under rapid charge–discharge conditions.
Over the past 30 years, significant commercial and academic progress has been made on Li‐based battery technologies. From the early Li‐metal anode iterations to the current commercial Li‐ion ...batteries (LIBs), the story of the Li‐based battery is full of breakthroughs and back tracing steps. This review will discuss the main roles of material science in the development of LIBs. As LIB research progresses and the materials of interest change, different emphases on the different subdisciplines of material science are placed. Early works on LIBs focus more on solid state physics whereas near the end of the 20th century, researchers began to focus more on the morphological aspects (surface coating, porosity, size, and shape) of electrode materials. While it is easy to point out which specific cathode and anode materials are currently good candidates for the next‐generation of batteries, it is difficult to explain exactly why those are chosen. In this review, for the reader a complete developmental story of LIB should be clearly drawn, along with an explanation of the reasons responsible for the various technological shifts. The review will end with a statement of caution for the current modern battery research along with a brief discussion on beyond lithium‐ion battery chemistries.
The major development events in the history of lithium‐ion batteries are presented and the driving forces responsible for the various technological shifts are discussed.
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•The idea of “waste+waste→resources.” was used on this study.•Based on thermodynamic analysis, the possible reaction between LiCoO2 and graphite was obtained.•The residues of ...oxygen-free roasting are cobalt, lithium carbonate and graphite.•The recovery rate of Co and Li is 95.72% and 98.93% after wet magnetic separation.•It provides the rationale for environmental-friendly recycling spent LIBs in industrial-scale.
The definite aim of the present paper is to present some novel methods that use oxygen-free roasting and wet magnetic separation to in situ recycle of cobalt, Lithium Carbonate and Graphite from mixed electrode materials. The in situ recycling means to change waste into resources by its own components, which is an idea of “waste+waste→resources.” After mechanical scraping the mixed electrode materials enrich powders of LiCoO2 and graphite. The possible reaction between LiCoO2 and graphite was obtained by thermodynamic analysis. The feasibility of the reaction at high temperature was studied with the simultaneous thermogravimetry analysis under standard atmospheric pressure. Then the oxygen-free roasting/wet magnetic separation method was used to transfer the low added value mixed electrode materials to high added value products. The results indicated that, through the serious technologies of oxygen-free roasting and wet magnetic separation, mixture materials consist with LiCoO2 and graphite powders are transferred to the individual products of cobalt, Lithium Carbonate and Graphite. Because there is not any chemical solution added in the process, the cost of treating secondary pollution can be saved. This study provides a theoretical basis for industrial-scale recycling resources from spent LIBs.
The high nickel ternary cathode materials LiNi0.815Co0.15Al0.035O2 (NCA) have been widely used in Li-ion batteries due to their high energy density, low cost, and little environmental pollution. ...However, it suffers from rapid capacity degradation and poor charging rate. In this work, Ti4+ doping NCA cathode materials are prepared by the high-temperature solid-state method. The results show that 0.5%Ti-NCA has a lower cationic mixing degree and better cycling performance. The capacity retention rate of 100 cycles is 98.91% and 96.59% at current densities of 0.5 C and 1.0 C, respectively. The CV and EIS test results show that 0.5%Ti-NCA has lower polarization and higher lithium ion diffusion coefficient DLi+(8.43×10−14 cm2/S) after 100 cycles, while Pure-NCA only has 6.92×10−15 cm2/S, which effectively enhances the electrochemical properties of NCA cathode materials.
•Ti4+ hinders the cross-layer migration of Ni2+ and further reduces the cation mixing.•The charge compensation function of Ti4+ makes it have excellent performances.•The diffusion rate of Li+ increases due to Ti4+ increases the lattice parameter c.
Flexible thin film all-solid-state Li-ion batteries are considered as promising candidates to power a multitude of flexible and miniaturized electronic devices. The production of crystalline battery ...active materials generally involves high process temperatures above 500 °C. One current challenge in mechanically flexible thin film electrode fabrication is the direct deposition of such crystalline active materials onto temperature sensitive substrates. In the current work we have made a paradigm shift depositing highly pure crystalline Li4Ti5O12 nanoparticles onto a flexible polyimide foil in a single step using flame spray pyrolysis technique. The Li4Ti5O12 films were mechanically compressed at room temperature to 0.55 µm thin layers, to enhance their adhesion to the substrates, i.e. to increase mechanical stability. The smooth Li4Ti5O12 electrodes were covered with a solid electrolyte and tested against lithium metal electrodes. Stable electrochemical cycling behavior of the battery cells demonstrated the feasibility of the proposed technique for LTO thin film electrode fabrication on temperature sensitive and mechanically flexible polyimide substrates. Fundamental data on possible electrode cyclability upon electrode bending was obtained by successful cycling of LTO flex-TFBs in statically bent condition. This study could initialize a new branch for facile manufacturing of flexible thin film battery cells.
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•Deposition of crystalline Li4Ti5O12 particles on flexible polymer substrates avoiding heat-treatments.•Assembling Li4Ti5O12 thin film electrodes in flexible all-solid-state battery cells.•Stable electrochemical cycling behavior of all-solid-state battery cells in flat and bent condition.
•A novel fibre sensing technology is proposed to deliver a distributed, real-time and accurate measure of temperature for battery cell.•The thermal behaviour of a pouch cell is experimentally ...investigated over a wide range of ambient temperatures and electrical load currents.•A distributed fibre sensor is used to measure both the in-plane gradient across the cell surface and the movement of the hottest region of the cell during operation.•The fibre results highlight that the maximum in-plane temperature gradient was found to be up to 307% higher than that measured using traditional a thermocouple approach.
Real-time temperature monitoring of li-ion batteries is widely regarded within the both the academic literature and by the industrial community as being a fundamental requirement for the reliable and safe operation of battery systems. This is particularly evident for larger format pouch cells employed in many automotive or grid storage applications. Traditional methods of temperature measurement, such as the inclusion of individual sensors mounted at discrete locations on the surface of the cell may yield incomplete information. In this study, a novel Rayleigh scattering based optical fibre sensing technology is proposed and demonstrated to deliver a distributed, real-time and accurate measure of temperature that is suitable for use with Li-ion pouch cells. The thermal behaviour of an A5-size pouch cell is experimentally investigated over a wide range of ambient temperatures and electrical load currents, during both charge and discharge. A distributed fibre optical sensor (DFOS) is used to measure both the in-plane temperature difference across the cell surface and the movement of the hottest region of the cell during operation, where temperature difference is the difference of temperature amongst different measuring points. Significantly, the DFOS results highlight that the maximum in-plane temperature difference was found to be up to 307% higher than that measured using traditional a thermocouple approach.
N and S codoping of graphene is realized by a novel approach: covalent functionalization of graphene oxide using 2‐aminothiophenol as a source of both N and S followed by thermal treatment. The ...resulting N‐ and S‐codoped graphene has potential applications in high‐performance lithium‐ion batteries and as a metal‐free catalyst for oxygen reduction reaction.
Engineering electrode nanostructures is critical in developing high‐capacity, fast rate‐response, and safe Li‐ion batteries. This study demonstrates the synthesis of orthorhombic Nb2O5@Nb4C3Tx (or ...@Nb2CTx) hierarchical composites via a one‐step oxidation —in flowing CO2 at 850 °C —of 2D Nb4C3Tx (or Nb2CTx) MXene. The composites possess a layered architecture with orthorhombic Nb2O5 nanoparticles decorated uniformly on the surface of the MXene flakes and interconnected by disordered carbon. The composites have a capacity of 208 mAh g−1 at a rate of 50 mA g−1 (0.25 C) in 1–3 V versus Li+/Li, and retain 94% of the specific capacity with 100% Coulombic efficiency after 400 cycles. The good electrochemical performances could be attributed to three synergistic effects: (1) the high conductivity of the interior, unoxidized Nb4C3Tx layers, (2) the fast rate response and high capacity of the external Nb2O5 nanoparticles, and (3) the electron “bridge” effects of the disordered carbon. This oxidation method was successfully extended to Ti3C2Tx and Nb2CTx MXenes to prepare corresponding composites with similar hierarchical structures. Since this is an early report on producing this structure, there is much room to push the boundaries further and achieve better electrochemical performance.
The oxidation of Nb4C3Tx MXene in CO2 results in a hierarchical T‐Nb2O5@Nb4C3Tx layered composite, that combines the high capacity of the external orthorhombic T‐Nb2O5, coupled with the high electrical conductivity of the interior unoxidized Nb4C3Tx and the electron bridge effect of the disordered carbon. This composite exhibits high capacity at high rate when used as Li‐ion battery anode.
Intentionally inducing worst-case thermal runaway scenarios in Li-ion cells on-demand is a definitive way to test the efficacy of battery systems in safely mitigating the consequences of catastrophic ...failure. An internal short-circuiting (ISC) device is implanted into three 18650 cell designs: one standard, one with a bottom vent, and one with a thicker casing. Through an extensive study of 228 cells, the position at which thermal runaway initiates is shown to greatly affect the tendency of cells to rupture and incur side-wall breaches at specific locations. The risks associated with each failure mechanism and position of the ISC device are quantified using a custom calorimeter that can decouple the heat from ejected and non-ejected contents. Causes of high-risk failure mechanisms, such as bursting and side-wall breaches, are elucidated using high-speed synchrotron X-ray imaging at 2000 frames per second and image-based 3D thermal runaway computational models, which together are used to construct a comprehensive description of external risks based on internal structural and thermal phenomena.
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