A novel flame‐retardant electrolyte additive for safer lithium‐ion batteries

Abstract

Summary Lithium‐ion batteries (LIBs) have attracted much attention in the field of new energy. However, due to the flammability of its electrolyte, the batteries may have fire or even explosion accidents in unconventional environment. We have synthesized a new electrolyte additive, 1‐diphenylphosphoryloxy‐4‐methylbenzene (DPMB), in the hope of improving the safety performance of LIBs by combining flame‐retardant and overcharge protection. According to the results of the self‐extinguishing time test and the differential scanning calorimetry test, it can see that the addition of DPMB can improve the flame retardancy of original electrolytes. Unfortunately, the electrochemical test results show that the oxidation potential of DPMB is 3.8 V, which indicate that DPMB cannot achieve the role of overcharge protection. But it is interesting that the addition of DPMB not only has no side effects on the LIBs performance, but also improves the cycle performance and rate capability of the LIBs to a certain extent, especially when the DPMB content is 2wt%. Our results provide a new choice of additives for improving the safety of LIBs electrolyte.

Thermal Effect and Mechanism Analysis of Flame-Retardant Modified Polymer Electrolyte for Lithium-Ion Battery

“…The net electrolyte content in the sample pan was 6.5 ± 0.5 mg. The samples were heated from 30 to 350 °C at heating rates of 1, 2, 4, 7, and 10 °C/min [ 22 , 23 , 24 , 25 , 26 ]. By comparing the thermal stability parameters (initial reaction temperature ( T o ), peak temperature ( T p ), and end reaction temperature ( T e ), the thermal behavior of the standard electrolyte and flame-retardant electrolyte were evaluated [ 27 , 28 , 29 , 30 ].…”

Challenges for Safe Electrolytes Applied in Lithium-Ion Cells—A Review

“…It should be remembered that this parameter depends on many factors, such as the type and composition of the electrolyte, the type of additives used for the electrolyte, and the speed of the charge/discharge process [43,44]. The desired effect is the complete creation of the SEI before starting the lithium intercalation process (>0.3 V vs. Li/Li + [45]). This is more difficult to achieve in the case of disordered coals, because for some of them, the insertion process starts at approximately 1.5 V vs. Li/Li + , compared to structured carbons with an insertion potential of approximately 0.25 V [46].…”

Abuse‐Tolerant Electrolytes for Lithium‐Ion Batteries

“…It is ideal to develop new fascinating materials that possess all the abuse-resistant properties in electrolytes, thus to greatly improve the safety issues of LIBs and promote the use of lithium-ion batteries in grid energy systems and create a more sustainable society. Bifunctional additives containing flame-retardant functional groups (e.g., fluorine-, phosphorus-, sulfur-, or boron-containing functional groups) and polymerizable redox shuttle functionalities could be synthesized as a fascinating additive candidate (e.g., (4-methoxy)-phenoxy pentafluorocyclotriphosphazene, [79] 1-diphenylphosphoryloxy-4methylbenzene [80] ), which may enable the formation of electrolytes that hinder the flame propagation/ignition of electrolytes due to the radical absorption and oxygen isolation mechanism as well as limit the battery voltage within a safe range against overcharge by forming a passivation layer. [79][80][81] In the past, a timeconsuming and inefficient trial-and-error approach has been applied to develop specific additives for use in the abuse-resistant electrolytes, which is an individual selection method.…”

“…Bifunctional additives containing flame-retardant functional groups (e.g., fluorine-, phosphorus-, sulfur-, or boron-containing functional groups) and polymerizable redox shuttle functionalities could be synthesized as a fascinating additive candidate (e.g., (4-methoxy)-phenoxy pentafluorocyclotriphosphazene, [79] 1-diphenylphosphoryloxy-4methylbenzene [80] ), which may enable the formation of electrolytes that hinder the flame propagation/ignition of electrolytes due to the radical absorption and oxygen isolation mechanism as well as limit the battery voltage within a safe range against overcharge by forming a passivation layer. [79][80][81] In the past, a timeconsuming and inefficient trial-and-error approach has been applied to develop specific additives for use in the abuse-resistant electrolytes, which is an individual selection method. Currently, high-throughput screening techniques have become popular and powerful in the discovery of novel materials, the prediction of physical and chemical properties based on big data owing to their prediction accuracy and low cost for computation.…”