Multifunctional Fluoroethylene Carbonate for Improving High-Temperature Performance of LiNi_0.8Mn_0.1Co_0.1O₂||SiO_x@Graphite Lithium-Ion Batteries

Abstract

LiNi 0.8 Mn 0.1 Co 0.1 O 2 ||SiO x @graphite has received great attention in both academia and industry because it has the highest energy density among state-of-the-art commercial lithium-ion batteries. However, it suffers from severe capacity decay during high-temperature cycling or storage, which still needs to be addressed for its commercialization. In this work, fluoroethylene carbonate (FEC) is employed as an additive or a cosolvent to improve the high-temperature performance of 1 Ah LiNi 0.8 Mn 0.1 Co 0.1 O 2 ||SiO x @graphite pouch cells. By adding 5% FEC as additive, the capacity retention increases from 54.5% to 67.0% after 100 cycles at 45 °C. The use of FEC as a cosolvent further increases the capacity retention to 83.3%. The improvement is ascribed to the multifunctional effects from FEC, preventing electrolyte decomposition, mitigating the resistance increment and Mn ions dissolution with the formation of the interface films, which consist of LiF and LiPO x F y species. Therefore, the employment of FEC is of great importance for the development of high-energy-density lithium-ion batteries.

Isocyanate Additives Improve the Low-Temperature Performance of LiNi0.8Mn0.1Co0.1O2||SiOx@Graphite Lithium-Ion Batteries

“…8 The battery based on NMC811 and SiO x @G has a working voltage platform capable of reaching over 3.6 V, 9,10 which can provide a high energy density (>350 Wh kg −1 ). 11,12 Consequently, NMC811||SiO x @G has good prospects in the fields of next-generation energy storage devices and electric vehicles. 13 One of the main issues of the LIB is poor environmental adaptability; that is, the energy and power densities of the battery decrease remarkably in the low-temperature condition.…”

“…The battery based on NMC811 and SiO x @G has a working voltage platform capable of reaching over 3.6 V, , which can provide a high energy density (>350 Wh kg –1 ). , Consequently, NMC811||SiO x @G has good prospects in the fields of next-generation energy storage devices and electric vehicles …”

Recent progress on performance modulation and mechanism study of silicon-based anodes

“…Using uoroethylene carbonate as an electrolyte additive was reported recently that can effectively prevent the decomposition of the electrolyte and result in a thin SEI lm, thus improving the stability of the SiO x @graphite anode. 68 Although pristine SiO x anode materials possess electrochemically inert phases (Li 4 SiO 4 and Li 2 O) to relieve the volume expansion, their ICE will be lowered by the huge lithium consumption during the rst cycle. To address the above shortcomings, more modications (such as designing a porous structure, size reduction, cost control, low-cost prelithiation technology, high-performance electrolytes, binders, etc.)…”

“…Using fluoroethylene carbonate as an electrolyte additive was reported recently that can effectively prevent the decomposition of the electrolyte and result in a thin SEI film, thus improving the stability of the SiO x @graphite anode. 68…”

Thermal Runaway of Nonflammable Localized High‐Concentration Electrolytes for Practical LiNi0.8Mn0.1Co0.1O2|Graphite‐SiO Pouch Cells

“…[1][2][3][4] To further increase the energy density, Ni-rich layered oxides with the high capacity have recently become the mainstream cathodes for practical LIBs, whereas the anode material is changing from graphite to a mixture of SiO and graphite. [5][6][7][8] Owing to the highest energy density among current commercial LIBs, LiNi 0.8 Mn 0.1 Co 0.1 O 2 |Graphite-SiO (NMC811|Gr-SiO) cell has attracted tremendous interest in both academic and industrial research. However, the electrode materials with higher energy density generally have lower thermal stability, leading to severe safety hazards characterized thermal runaway (TR), especially at high working voltage.…”