scholarly journals Multilayer Nanofiber Composite Separator for Lithium-Ion Batteries with High Safety

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1671 ◽  
Author(s):  
Wenxiu Yang ◽  
Yanbo Liu ◽  
Xuemin Hu ◽  
Jinbo Yao ◽  
Zhijun Chen ◽  
...  
Keyword(s):  
Adhesion Force ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Al2o3 Nanoparticles ◽  
Electrospun Nanofiber ◽  
Koch Curve ◽  
Nanofiber Composite ◽  
Battery Separator ◽  
Composite Separator ◽  
Polyethylene Powder

An original Von Koch curve-shaped tipped electrospinneret was used to prepare a polyimide (PI)-based nanofiber membrane. A multilayer Al2O3@polyimide/polyethylene/Al2O3@polyimide (APEAP) composite membrane was tactfully designed with an Al2O3@ polyimide (AP) membrane as outer shell, imparting high temperature to the thermal run-away separator performance and a core polyethylene (PE) layer imparts the separator with a thermal shut-down property at low temperature (123 °C). An AP electrospun nanofiber was obtained by doping Al2O3 nanoparticles in PI solution. The core polyethylene layer was prepared using polyethylene powder and polyterafluoroethylene (PTFE) miniemulsion through a coating process. The addition of PTFE not only bonds PE power, but also increases the adhesion force between the PE and AP membranes. As a result, the multilayer composite separator has high safety, outstanding electrochemical properties, and better cycling performance as a lithium-ion battery separator.

scholarly journals Aramid Nanofibers Reinforced Cellulose Paper-Based Lithium-Ion Battery Separator with Improved Safety and Cycling Stability

2021 ◽  
Author(s):  
Sufeng Zhang ◽  
Jin Luo ◽  
Min Du ◽  
Hongying Hui
Keyword(s):  
Electrochemical Performance ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Interfacial Resistance ◽  
Safety Hazards ◽  
Battery Separator ◽  
Electrolyte Uptake ◽  
Dimensional Shrinkage ◽  
Composite Separator

Abstract Commercial polyolefin separators with poor electrolyte wettability and inferior thermal stability have hampered the development of advanced lithium-ion batteries (LIBs) due to their unsatisfied electrochemical performance and severe safety hazards. Herein, a novel paper-based composite separator composed of electrolyte-affinitive cellulose fibers (CFs) and thermally stable aramid nanofibers (ANFs) was successfully fabricated through the traditional papermaking method. It was found that the incorporation of ANFs played crucial roles in improving the defects of pure CF separator such as large-sized pores, low mechanical strength and high flammability. Specifically, the CF/ANF composite separator with 20 wt.% ANFs (CF/ANF-20) possessed narrow micropores, satisfied tensile strength (33MPa), excellent thermal resistance (without dimensional shrinkage up to 200 °C) and flame retardancy, greatly enhancing the safe operation of battery. In addition, benefiting from the highly porous structure and exceptional electrolyte affinity of CF separator, the CF/ANF-20 composite separator exhibited appropriate porosity and superior electrolyte wettability, which brought about a high electrolyte uptake (157%), thus endowing it with better ionic conductivity (0.75 mS cm−1) and lower interfacial resistance than that of commercial polypropylene (PP) separator. Accordingly, the LiFePO4/Li half cells using CF/ANF-20 separator delivered outstanding rate capability and stable cycling performance. All results indicate that the CF/ANF-20 separator with great balance between the electrochemical performance and safety is an intriguing candidate for advanced LIBs.

scholarly journals Enhancement of Thermal Stability and Cycling Performance of Lithium-Ion Battery at High Temperature by Nano-ppy/OMMT-Coated Separator

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Shuo Yang ◽  
Huiya Qin ◽  
Xuan Li ◽  
Huijun Li ◽  
Pei Yao
Keyword(s):  
Thermal Stability ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Internal Resistance ◽  
Covalent Bonds ◽  
Excellent Thermal Stability ◽  
Composite Separator ◽  
Hydrolysis Of ◽  
Coated Separator

Nanopolypyrrole/organic montmorillonite- (nano-ppy/OMMT-) coated separator is prepared by coating nano-ppy/OMMT on the surface of polyethylene (PE). Nano-ppy/OMMT-coated separator with three-dimensional and multilayered network structure is beneficial to absorb more organic electrolyte, enhancing the ionic conductivity (reach 4.31 mS·cm-1). Meanwhile, the composite separator exhibits excellent thermal stability and mechanical properties. The strong covalent bonds (Si-F) are formed by the nucleophilic substitution reaction between F−from the thermal decomposition and hydrolysis of LiPF6and the covalent bonds (Si-O) of nano-ppy/OMMT. The Si-F can effectively prevent the formation of HF, POF3, and LiF, resulting in the inhibition of the disproportionation of Mn3+in LiNi1/3Co1/3Mn1/3O2material as well as reducing the internal resistance of the cell. Therefore, the nano-ppy/OMMT-coated separator exhibits outstanding capacity retention and cycling performance at 80°C.

scholarly journals A cooperative biphasic MoOx–MoPx promoter enables a fast-charging lithium-ion battery

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sang-Min Lee ◽  
Junyoung Kim ◽  
Janghyuk Moon ◽  
Kyu-Nam Jung ◽  
Jong Hwa Kim ◽  
...  
Keyword(s):  
Anode Materials ◽  
Surface Engineering ◽  
Dominant Role ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Graphite Anode ◽  
Graphite Surface ◽  
High Rate ◽  
Fast Charging ◽  
Li Ion

AbstractThe realisation of fast-charging lithium-ion batteries with long cycle lifetimes is hindered by the uncontrollable plating of metallic Li on the graphite anode during high-rate charging. Here we report that surface engineering of graphite with a cooperative biphasic MoOx–MoPx promoter improves the charging rate and suppresses Li plating without compromising energy density. We design and synthesise MoOx–MoPx/graphite via controllable and scalable surface engineering, i.e., the deposition of a MoOx nanolayer on the graphite surface, followed by vapour-induced partial phase transformation of MoOx to MoPx. A variety of analytical studies combined with thermodynamic calculations demonstrate that MoOx effectively mitigates the formation of resistive films on the graphite surface, while MoPx hosts Li+ at relatively high potentials via a fast intercalation reaction and plays a dominant role in lowering the Li+ adsorption energy. The MoOx–MoPx/graphite anode exhibits a fast-charging capability (<10 min charging for 80% of the capacity) and stable cycling performance without any signs of Li plating over 300 cycles when coupled with a LiNi0.6Co0.2Mn0.2O2 cathode. Thus, the developed approach paves the way to the design of advanced anode materials for fast-charging Li-ion batteries.

scholarly journals Dealloying-Derived Nanoporous Cu6Sn5 Alloy as Stable Anode Materials for Lithium-Ion Batteries

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4348
Author(s):  
Chi Zhang ◽  
Zheng Wang ◽  
Yu Cui ◽  
Xuyao Niu ◽  
Mei Chen ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Anode Materials ◽  
Coulombic Efficiency ◽  
Lithium Ion ◽  
Specific Area ◽  
Cycling Performance ◽  
Ex Situ ◽  
Li Ion ◽  
Xrd Patterns ◽  
Cu6sn5 Alloy

The volume expansion during Li ion insertion/extraction remains an obstacle for the application of Sn-based anode in lithium ion-batteries. Herein, the nanoporous (np) Cu6Sn5 alloy and Cu6Sn5/Sn composite were applied as a lithium-ion battery anode. The as-dealloyed np-Cu6Sn5 has an ultrafine ligament size of 40 nm and a high BET-specific area of 15.9 m2 g−1. The anode shows an initial discharge capacity as high as 1200 mA h g−1, and it remains a capacity of higher than 600 mA h g−1 for the initial five cycles at 0.1 A g−1. After 100 cycles, the anode maintains a stable capacity higher than 200 mA h g−1 for at least 350 cycles, with outstanding Coulombic efficiency. The ex situ XRD patterns reveal the reverse phase transformation between Cu6Sn5 and Li2CuSn. The Cu6Sn5/Sn composite presents a similar cycling performance with a slightly inferior rate performance compared to np-Cu6Sn5. The study demonstrates that dealloyed nanoporous Cu6Sn5 alloy could be a promising candidate for lithium-ion batteries.

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