Liquefied gas electrolytes for electrochemical energy storage devices

Abstract

Electrochemical capacitors and lithium-ion batteries have seen little change in their electrolyte chemistry since their commercialization, which has limited improvements in device performance. Combining superior physical and chemical properties and a high dielectric-fluidity factor, the use of electrolytes based on solvent systems that exclusively use components that are typically gaseous under standard conditions show a wide potential window of stability and excellent performance over an extended temperature range. Electrochemical capacitors using difluoromethane show outstanding performance from -78° to +65°C, with an increased operation voltage. The use of fluoromethane shows a high coulombic efficiency of ~97% for cycling lithium metal anodes, together with good cyclability of a 4-volt lithium cobalt oxide cathode and operation as low as -60°C, with excellent capacity retention.

High‐Energy Rechargeable Metallic Lithium Battery at −70 °C Enabled by a Cosolvent Electrolyte

“…[1] To achieve the low-T operation for rechargeable batteries,many efforts have been focused on modifying the electrolyte formulation, such as the utilization of mixed solvents, [2] novel salts and electrolyte additives, [3] and new solvents. [4] Recently,e thyl acetate (EA) was reported to facilitate the operation of rechargeable LIBs at alow TofÀ70 8 8C, [4b] owing to its much lower freezing point of À84 8 8Ct han conventional solvents (Table S1 in the Supporting Information). Unfortunately,an ew challengethe narrow electrochemical window (1.5-4.7 V, vs.L i + /Li)o f the 2mol kg À1 EA-based electrolyte-hinders the application of the Li metal anode for high energy-density batteries.Thus, an ovel electrolyte with enhanced stability to Li-metal is of importance.R esearches show that highly concentrated electrolytes exhibited enhanced oxidative/reductive stability, which offered as olution for an expanded electrochemical stable potential window.…”

A Simple Prelithiation Strategy To Build a High‐Rate and Long‐Life Lithium‐Ion Battery with Improved Low‐Temperature Performance

“…Very recently, Meng et al. reported the liquefied gas electrolyte for Li‐metal batteries that exhibit high performance at a temperature of −60 °C . However, high pressure stainless steel cells had to be used during the electrochemical tests, because the electrolyte is typically gaseous under standard conditions.…”

Excellent Rate and Low Temperature Performance of Lithium‐Ion Batteries based on Binder‐Free Li4Ti5O12 Electrode

“…The organic electrodes‐based full cell LIB assembled using an Ethyl acetate (EA)‐based electrolyte realized 69 % of its theoretical capacity at 200 C under room temperature and 69 mAh g −1 at −70 °C under 0.5 C . The liquid gas electrolyte systems were used to extend the LIBs work temperature range, LiCoO 2 showed the 60.6 % capacity retention at 0.1 C under −60 °C …”

“…The organic electrodes-based full cell LIB assembled using an Ethyl acetate (EA)-based electrolyte realized 69 % of its theoretical capacity at 200 C under room temperature and 69 mAh g À 1 at À 70°C under 0.5 C. [9] The liquid gas electrolyte systems were used to extend the LIBs work temperature range, LiCoO 2 showed the 60.6 % capacity retention at 0.1 C under À 60°C. [10] In order to improve the low temperature-tolerant performance of LIBs, lithium insertion/extraction in the positive and negative materials at low temperature must be solved synergistically. High rate at room temperature is the premise of improving battery performance at low temperature.…”