scholarly journals Butyronitrile-Based Electrolytes for Fast Charging of Lithium-Ion Batteries

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2869 ◽  
Author(s):  
Peter Hilbig ◽  
Lukas Ibing ◽  
Martin Winter ◽  
Isidora Cekic-Laskovic

After determining the optimum composition of the butyronitrile: ethylene carbonate: fluoroethylene carbonate (BN:EC:FEC) solvent/co-solvent/additive mixture, the resulting electrolyte formulation (1M LiPF6 in BN:EC (9:1) + 3% FEC) was evaluated in terms of ionic conductivity and the electrochemical stability window, as well as galvanostatic cycling performance in NMC/graphite cells. This cell chemistry results in remarkable fast charging, required, for instance, for automotive applications. In addition, a good long-term cycling behavior lasts for 1000 charge/discharge cycles and improved ionic conductivity compared to the benchmark counterpart was achieved. XPS sputter depth profiling analysis proved the beneficial behavior of the tuned BN-based electrolyte on the graphite surface, by confirming the formation of an effective solid electrolyte interphase (SEI).

Author(s):  
Kuber Mishra ◽  
Wu Xu ◽  
Mark H. Engelhard ◽  
Ruiguo Cao ◽  
Jie Xiao ◽  
...  

A thin and mechanically stable solid electrolyte interphase (SEI) is desirable for a stable cyclic performance in a lithium ion battery. For the electrodes that undergo a large volume expansion, such as Si, Ge, and Sn, the presence of a robust SEI layer can improve the capacity retention. In this work, the role of solvent choice on the electrochemical performance of Ge electrode is presented by a systematic comparison of the SEI layers in ethylene carbonate (EC)-based and fluoroethylene carbonate (FEC)-based electrolytes. The results show that the presence of FEC as a cosolvent in a binary or ternary solvent electrolyte results in an excellent capacity retention of ∼85% after 200 cycles at the current density of 500 mA g−1; while EC-based electrode suffers a rapid capacity degradation with a capacity retention of just 17% at the end of 200 cycles. Post analysis by an extensive use of X-ray photoelectron spectroscopy (XPS) was carried out, which showed that the presence of Li2O in FEC-based SEIs was the origin for the improved electrochemical performance.


2020 ◽  
Author(s):  
Nadia Intan ◽  
Jim Pfaendtner

The formation of a solid electrolyte interphase (SEI) at the electrode/electrolyte interface substantially affects the stability and lifetime of lithium-ion batteries (LIBs). One of the methods to improve the lifetime of LIBs is by the inclusion of additive molecules to stabilize the SEI. To understand the effect of additive molecules on the initial stage of SEI formation, we compare the decomposition and oligomerization reactions of a fluoroethylene carbonate (FEC) additive on a range of oxygen functionalized graphitic anode to those of an ethylene carbonate (EC) organic electrolyte. A series of density functional theory (DFT) calculations augmented by ab-initio molecular dynamics (AIMD) simulations reveal that EC decomposition on an oxygen functionalized graphitic (1120) edge facet through an SN2 mechanism is spontaneous, even in an uncharged cell. Decomposition of EC through an SN2 reaction pathway results in alkoxide species regeneration which is responsible for continual oligomerization along the graphitic surface. In contrast, FEC prefers to decompose through an SN1 pathway, which does not promote alkoxide regeneration. The ability of FEC as an additive to suppress alkoxide regeneration results in a smaller and thinner SEI layer that is more flexible towards lithium intercalation during the charging/discharging process. In addition, the presence of different oxygen functional groups at the surface of graphite dictates the oligomerization products and LiF formation in the SEI.


2020 ◽  
Author(s):  
Nadia Intan ◽  
Jim Pfaendtner

The formation of a solid electrolyte interphase (SEI) at the electrode/electrolyte interface substantially affects the stability and lifetime of lithium-ion batteries (LIBs). One of the methods to improve the lifetime of LIBs is by the inclusion of additive molecules to stabilize the SEI. To understand the effect of additive molecules on the initial stage of SEI formation, we compare the decomposition and oligomerization reactions of a fluoroethylene carbonate (FEC) additive on a range of oxygen functionalized graphitic anode to those of an ethylene carbonate (EC) organic electrolyte. A series of density functional theory (DFT) calculations augmented by ab-initio molecular dynamics (AIMD) simulations reveal that EC decomposition on an oxygen functionalized graphitic (1120) edge facet through an SN2 mechanism is spontaneous, even in an uncharged cell. Decomposition of EC through an SN2 reaction pathway results in alkoxide species regeneration which is responsible for continual oligomerization along the graphitic surface. In contrast, FEC prefers to decompose through an SN1 pathway, which does not promote alkoxide regeneration. The ability of FEC as an additive to suppress alkoxide regeneration results in a smaller and thinner SEI layer that is more flexible towards lithium intercalation during the charging/discharging process. In addition, the presence of different oxygen functional groups at the surface of graphite dictates the oligomerization products and LiF formation in the SEI.


Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 989
Author(s):  
Feihu Tan ◽  
Hua An ◽  
Ning Li ◽  
Jun Du ◽  
Zhengchun Peng

All-solid-state batteries (ASSBs) are attractive for energy storage, mainly because introducing solid-state electrolytes significantly improves the battery performance in terms of safety, energy density, process compatibility, etc., compared with liquid electrolytes. However, the ionic conductivity of the solid-state electrolyte and the interface between the electrolyte and the electrode are two key factors that limit the performance of ASSBs. In this work, we investigated the structure of a Li0.33La0.55TiO3 (LLTO) thin-film solid electrolyte and the influence of different interfaces between LLTO electrolytes and electrodes on battery performance. The maximum ionic conductivity of the LLTO was 7.78 × 10−5 S/cm. Introducing a buffer layer could drastically improve the battery charging and discharging performance and cycle stability. Amorphous SiO2 allowed good physical contact with the electrode and the electrolyte, reduced the interface resistance, and improved the rate characteristics of the battery. The battery with the optimized interface could achieve 30C current output, and its capacity was 27.7% of the initial state after 1000 cycles. We achieved excellent performance and high stability by applying the dense amorphous SiO2 buffer layer, which indicates a promising strategy for the development of ASSBs.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sang-Min Lee ◽  
Junyoung Kim ◽  
Janghyuk Moon ◽  
Kyu-Nam Jung ◽  
Jong Hwa Kim ◽  
...  

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.


2016 ◽  
Vol 191 ◽  
pp. 200-206 ◽  
Author(s):  
Liangtao Yang ◽  
Yonggao Xia ◽  
Xu Fan ◽  
Laifen Qin ◽  
Bao Qiu ◽  
...  

2016 ◽  
Vol 4 (35) ◽  
pp. 13646-13651 ◽  
Author(s):  
Cheng Zheng ◽  
Minying Liu ◽  
Wenqiang Chen ◽  
Lingxing Zeng ◽  
Mingdeng Wei

A Se/CMK-3 composite was in situ synthesized, exhibiting large capacity, high rate performance and excellent long-term cycling stability for Li-ion intercalation.


2013 ◽  
Vol 724-725 ◽  
pp. 1025-1028
Author(s):  
Rong Xiang ◽  
Fa Qiang Li ◽  
Guo Feng Jia ◽  
Zheng Jun Peng ◽  
Qin Zhuge

The low temperature performance of LiFePO4/Li cells based on lithium oxalyldifluoroborate (LiODFB) with fluoroethylene carbonate (FEC) as addictive have been investigated. The result of ionic conductivity test shows that the use of 5% FEC can improve the conductivity of both LiPF6and LiODFB electrolytes at low temperature. The electrochemical measurements of the cells show that the use of FEC can effectively improve the discharge capacity and has better kinetics characteristics and low temperature performance. The LiODFB cell with FEC also exhibits excellent cycling retention of 88.8% after 50 cycles at-20°C.


2016 ◽  
Vol 18 (12) ◽  
pp. 8643-8653 ◽  
Author(s):  
Yukihiro Okuno ◽  
Keisuke Ushirogata ◽  
Keitaro Sodeyama ◽  
Yoshitaka Tateyama

Additives in the electrolyte solution of lithium-ion batteries (LIBs) have a large impact on the performance of the solid electrolyte interphase (SEI) that forms on the anode and is a key to the stability and durability of LIBs.


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