Recent progress in nonflammable electrolytes and cell design for safe Li-ion batteries

Abstract

Nonaqueous lithium-ion batteries (LIBs) are critical energy storage technologies for portable electronics and electric vehicles owing to their high operating voltages (>3.5 V) and energy densities (~250 Wh kg–1). However,...

Advancements in flame-retardant strategies for lithium–sulfur batteries: from mechanisms to materials

“…The electrolyte commonly used in LSBs is a mixture of DOL : DEM = 1 : 1, 2% LiNO 3 , and 1 mol per L LiTFSI. 29,96 The ether electrolyte will release a lot of flammable gases when heated and the inner pressure will increase, which will lead to a deflagration phenomenon. 97 In addition, the low ignition points of the anode and cathode will make the electrode melt at high temperatures.…”

“…27,28 Thirdly, the poor thermal stability of separators such as polypropylene (PP) and polyethylene (PE) makes them easily shrink at high temperature, leading to an internal short-circuit. 29,30 Finally, the uneven deposition and shedding of Li + will lead to the growth of lithium dendrites under the condition of electric abuse, such as overcharge and high-speed charging. These dendrites may penetrate the separator, resulting in an internal short circuit and the accumulation of heat.…”

Solvation Structure and Derived Interphase Tuning for High‐Voltage Ni‐Rich Lithium Metal Batteries with High Safety Using Gem‐Difluorinated Ionic Liquid Based Dual‐Salt Electrolytes

“…[17] Thus fluorinated cations become highly scorching structures in the IL-based electrolytes, the encounter between fluorine and IL may be the key to solving the aforementioned bottleneck in company with fluorinated anions dominated solvation structure completing the multi-control of the interphase. [18] This is mainly related to the introduction of IL that brings plentiful anions into the Li + solvation sheath to form anions-derived interphase even at low concentrations of Li salts. In other words, the strategy of fluorinated IL cations can reduce the usage of Li salt obtaining a similar interfacial chemistry using lower Li salt concentration compared to high-concentration electrolytes (HCE).…”

“…That is to say, it would not only rely on the anions reduction to form a robust SEI layer, but the IL cations also can generate degradable substances on the Li surface to participate in the SEI layer [17] . Thus fluorinated cations become highly scorching structures in the IL‐based electrolytes, the encounter between fluorine and IL may be the key to solving the aforementioned bottleneck in company with fluorinated anions dominated solvation structure completing the multi‐control of the interphase [18] . This is mainly related to the introduction of IL that brings plentiful anions into the Li + solvation sheath to form anions‐derived interphase even at low concentrations of Li salts.…”