Lithium-ion batteries are favored by the electric vehicle (EV) industry due to their high energy density, good cycling performance and no memory. However, with the wide application of EVs, frequent ...thermal runaway events have become a problem that cannot be ignored. The following is a comprehensive review of the research work on thermal runaway of lithium-ion batteries. Firstly, the functions of each part of the battery and the related flame-retardant modification are summarized. The thermal properties of the battery are improved by means of coating of cathode materials and adding anion receptors. Secondly, the thermal runaway behavior and its triggering mechanism are introduced, and the decomposition reactions of common cathode materials are analyzed. Finally, the methods of thermal runaway monitoring and thermal management are summarized to provide the reference for the safety of lithium-ion batteries.
In order to solve the energy crisis, energy storage technology needs to be continuously developed. As an energy storage device, the battery is more widely used. At present, most electric vehicles are ...driven by lithium-ion batteries, so higher requirements are put forward for the capacity and cycle life of lithium-ion batteries. Silicon with a capacity of 3579 mAh·g
−1
is expected to replace graphite anode, but its large-scale application is limited by large volume expansion and unstable solid-electrolyte interface. At present, the modification methods of silicon mainly include nanocrystallization, silicon-carbon composite, and other methods. Nanocrystallization mainly reduces the mechanical stress of materials, and silicon-carbon composites can improve conductivity and alleviate volume expansion. This paper summarizes the current research and finally puts forward that only by optimizing the process flow and developing more environmentally friendly synthesis methods can we promote the commercialization of silicon anode materials.
Solid electrolyte is an important part of all-solid-state lithium-ion battery, and it is the key and difficult point in the research of all-solid-state lithium-ion battery. Both solid polymer ...electrolyte and inorganic ceramic electrolytes have obvious deficiencies in electrochemical and mechanical properties, but polymer-inorganic filler solid composite electrolyte is obtained by adding inorganic filler into solid polymer electrolyte and this way can complement their shortcomings. In this paper, the effect of inorganic fillers on lithium-ion migration in polymer electrolyte is analyzed. The latest research progress of solid composite electrolyte based on polyethylene oxide, polyacrylonitrile, and polycarbonate is introduced, which provides guidance for the research of solid composite electrolyte in the future.
To improve the stability of LiVPO4F electrode/electrolyte interface, Li3PO4 is used to modify LiVPO4F composite (P-LVPF) for the first time. Morphological characterization shows that LiVPO4F ...particles are wrapped by amorphous carbon and lithium ionic conductor Li3PO4 as the interlayer and outer layer, respectively. Compared to the pristine sample, the resultant P-LVPF exhibits greatly improved rate capability and elevated-temperature cycle performance when applied as the cathode material for lithium ion batteries. Specifically, the Li3PO4 modified sample specific capacity maintains 77.6% at 1 C after 100 cycles under 55 °C. Such improvement is attributed to the fact that the Li3PO4 coating layer not only acts as a good ionic conductor for LiVPO4F, but also serves as a physical barrier between electrode and electrolyte which can build a stable interface.
Display omitted
•Li3PO4 coating builds stable LiVPO4F/electrolyte interface for the first time.•LiVPO4F coated with Li3PO4 shows enhanced cycle performance at 55 °C.•Li3PO4 is proposed to act as a physical barrier as well as a Li+ transfer media.
The electrochemical technology and the density functional theory can provide a new idea for the intelligent detection and protection of Chinese traditional appliances. Lithium-ion battery is a ...typical electrochemical energy storage system, which is used as the core power supply component of sensor equipment to ensure the normal operation of intelligent monitoring and protection of cultural relics. The first-principles calculation method theoretically can prove the experimental results. The electrochemical properties of Ni-rich LiNi
1-x-y
Co
x
Mn
y
O
2
cathode materials were studied by doping or coating modification methods for the power supply used for intelligent monitoring and protection sensors. The results show that the modified material has a high capacity retention rate. The heat generation of the modified Ni-rich LiNi
1-x-y
Co
x
Mn
y
O
2
material is low, which can meet the requirements of use. This improved technology can solve the problems related to electrical power in intelligent detection and protection of Bronze Buddha of Shang Dynasty in China.
The irreversible phase transition of LiNi
0.5
Co
0.2
Mn
0.3
O
2
(NCM523) cathode materials easily occurs in high voltage (> 4.5 V) charging processes, which aggravates the corrosion of electrolyte on ...the materials and seriously affects the safety and cycling performance of lithium-ion batteries. In this paper, K and Cl ions were dual-doped into NCM523 by a high-temperature solid state method, and then Al
2
O
3
was coated on the surface of the NCM523 by a hydrothermal method to obtain the modified cathode materials. The crystal structure, morphology and surface state of the modified materials were analyzed, and the electrochemical performance was tested under high cut-off voltage (4.6 V). The results show that when the content of K and Cl dual-doping and Al
2
O
3
coating are 1 mol.% and 2 wt.%, respectively, the comprehensive properties of the materials are excellent. The first discharge capacity of 0.1 C is 210 mAh g
−1
, and the irreversible capacity loss is reduced. Compared with pristine materials, the specific discharge capacity at 5 C was increased by 26 mAh g
−1
, and the capacity retention rate was improved by 16% after 100 cycles at 1 C. The dual-doping of K and Cl ions can inhibit the mixing of cations, enhance the bond strength between transition metal cations and O
2−
, and improve the structural stability and the Li
+
transport rate. The Al
2
O
3
coating separates the cathode materials from the electrolyte and inhibits the corrosion of the electrolyte to the cathode materials. Therefore, the electrochemical properties of the modified cathode materials are significantly improved.
To address increasingly prominent energy problems, lithium-ion batteries have been widely developed. The high-nickel type nickel–cobalt–manganese (NCM) ternary cathode material has attracted ...attention because of its high energy density, but it has problems such as cation mixing. To address these issues, it is necessary to start from the surface and interface of the cathode material, explore the mechanism underlying the material's structural change and the occurrence of side reactions, and propose corresponding optimization schemes. This article reviews the defects caused by cation mixing and energy bands in high-nickel NCM ternary cathode materials. This review discusses the reasons why the core-shell structure has become an optimized high-nickel ternary cathode material in recent years and the research progress of core-shell materials. The synthesis method of high-nickel NCM ternary cathode material is summarized. A good theoretical basis for future experimental exploration is provided.
Surface coating and ion doping are of great significance for improving the electrochemical performance of cathode materials for lithium-ion batteries. In this study, WO
3
-coated and Mg
2+
-doped ...LiNi
0.8
Co
0.1
Mn
0.1
O
2
cathode materials were successfully synthesised by the coprecipitation and wet coating methods. X-ray diffraction and energy-dispersive X-ray spectroscopy confirmed that the synthesised material was NCM811 with a good layered structure and Mg
2+
doped into it. X-ray photoelectron spectroscopy revealed that W
6+
mainly existed on the surface of the material, while morphological analysis revealed a uniform WO
3
coating on the material surface. Electrochemical performance of the material suggested that the modification by suitable materials synergistically stabilised the material structure and suppressed side reactions. Capacity retention of the dual-modified material at 25 °C after 100 cycles at 1 C rate was as high as 73.5%, which is considerably higher than that of the raw materials (53.6%).
Silicon (Si) is a promising anode material for next-generation lithium-ion batteries (LIBs) with its high theoretical specific capacity (4200 mAh/g). However, Si anode has a huge volume change rate ...(> 300%) and high cost compared to graphite, which limits the commercial application of Si anode. Carbon coating can effectively tackle the volume change and poor conductivity during cycling of Si anode. In this work, aluminum–silicon alloy was firstly etched by hydrochloric acid. Followed by a mixture with pyrolysis of phenolic resin, the carbon layer outside the silicon particles was deposited during heat treatment process. The carbon-coated porous silicon-carbon (Si/C) anode material demonstrates excellent electrochemical performance and porous structure, which relieves mechanical stress and inhibits volume expansion. The results show that Si/C present well electrochemical performance at a sintering temperature of 800 ℃. Specially, the Si/C anode delivers a high specific capacity of 1394.4 mAh/g at the current density of 0.5 A/g with 46.1% retention. Nitrogen-doped silicon carbon composite material (Si/NC) was synthesized to further improve the performance of Si/C anodes. The characterizations confirm good crystallinity, uniform carbon coating on silicon surfaces, and even distribution of Si, C, and N elements. Simultaneously, a highly stable reversible capacity of 1218.3 mAh/g with 42.7% retention over 300 cycles at a current density of 0.5 A/g was obtained. This research can provide an alternative approach for high-energy and low-cost silicon-based anodes for LIBs.
PDF