Synergistic Flame Retardancy of Microcapsules Based on Ammonium Polyphosphate and Aluminum Hydroxide for Lithium-Ion Batteries

Abstract

Flame retardants have important theoretical research and applied value for lithium-ion battery safety. Microcapsule flame retardants based on ammonium polyphosphate (APP) and aluminum hydroxide (ATH) were synthesized for application in lithium-ion batteries. First, the ATH–APP was prepared by coating a layer of ATH on the surface of the core APP. Then, the ATH–APP was encapsulated by poly(urea-formaldehyde) (PUF) to obtain en-ATH–APP. The structure and flame-retardant property of en-ATH–APP, the influence of en-ATH–APP on the thermal stability of the electrode, and the electrochemical performance of the battery were studied. The results of Fourier transform infrared and scanning electron microscope experiments indicated that APP was coated with ATH and PUF in turn. The results of differential scanning calorimetry and the fire extinguishing test for electrodes manifested that en-ATH–APP had better flame-retardant property than APP because of the synergistic effect between APP and ATH. Moreover, the flame-retardant efficiency of en-ATH–APP was comparable to that of ATH–APP, indicating that the presence of PUF had almost no effect on the flame-retardant property. The results of electrochemical experiments indicated that en-ATH–APP had the best electrochemical compatibility for the battery compared with APP and ATH–APP. The research lights the way to improve inherent safety of lithium-ion batteries by adding en-ATH–APP to the cathode.

Thermomechanical and Fire Properties of Polyethylene-Composite-Filled Ammonium Polyphosphate and Inorganic Fillers: An Evaluation of Their Modification Efficiency

“…All spectra contain a minor peak around 1256 cm −1 , characteristic of the stretching vibrations of P=O bands present in polyphosphate structures [37]. Bands related to the vibrations of single phosphorous-oxygen bonds were also noted around 800 and 880 cm −1 [38]. Moreover, materials containing basalt and vermiculite fillers show small signals in the range 990-1010 cm −1 , typical for stretching Si-O bonds, as reported in previous work [39].…”

Recent Advances in Battery Pack Polymer Composites

“…This technique can also be applied to other single flame retardants as well as hybrid flame retardant combinations, which are subsequently processed through microencapsulation. Microencapsulated ATH and APP flame retardants perform better compared to untreated APP [124].…”

Bio‐Inspired Electrodes with Rational Spatiotemporal Management for Lithium‐Ion Batteries

“…[211] Furthermore, the element doping, surface coating, and optimization of the synthesis process in electrode materials enable to achieve significant electrochemical performance improvement on super high discharge capacity or capacity retention of LIBs. [100] Bio-inspired electrodes are developed with self-healing coreshell structure, [30][31][32][33][34][35] self-healing binders, [36][37][38][39][40] liquid metal alloys, [41][42][43][44][45][46] microcapsules, [48][49][50] and current collectors. [51] These electrodes owning self-healing capabilities possess much more stable mechanical characteristics than conventional electrode materials that can be shortened their durability by mechanical fractures generated during cycling.…”