TAP (Triallyl Phosphate, >99.0%) as Battery Electrolyte Additive, 5-25 g/bottle, CBEATAP

Triallyl Phosphate (TAP)—systematically named tri(prop-2-en-1-yl) phosphate—is an unsaturated organophosphorus functional additive featuring three reactive terminal allyl groups (-CH2-CH=CH2) bound to a central phosphate ester core (CH2=CH-CH2-O)3-P=O). It is widely used in non-aqueous electrolytes for high-voltage lithium-ion (LIBs), lithium-metal, and sodium-ion batteries to improve interphase stability and flame retardancy. The core functional roles & electrochemical advantages are shown below:

High-Voltage Cathode Electrolyte Interphase (CEI) Passivation: The presence of three reactive double bonds (C=C) gives TAP a relatively low oxidation potential compared to saturated carbonate solvents. During initial high-voltage charging (>4.3 V vs. Li/Li+), TAP oxidizes preferentially on active cathode surfaces (e.g., Ni-rich NMC811, NCMA, high-voltage LCO). Free-radical polymerization of the allyl arms creates a thin, cross-linked, phosphorus- and organic-rich CEI layer. This film acts as a physical barrier that passivates catalytic cathode surface sites and suppresses parasitic oxidation of the bulk solvent.

Suppression of Transition Metal Leaching: The basic phosphate oxygen (P=O) and allyl groups interact with surface transition-metal ions (Ni^{3+}/Ni^{4+}, Mn^{3+}) on high-voltage cathodes. Passivating these reactive sites inhibits transition-metal dissolution, mitigating structural phase transformations (such as layered-to-rocksalt transitions) and preventing dissolved metal ions from migrating to and poisoning the anode SEI.

Inorganic/Organic Hybrid Anode SEI Formation: TAP also participates in sacrificial reduction on graphite, silicon-carbon, or lithium-metal anodes at ~ 1.0 V to 1.3 V vs. Li/Li+. Polymerization of the allyl double bonds generates a flexible, organic-rich outer layer, while phosphate fragments contribute conductive inorganic phosphorus species to the inner interphase layer, helping homogenize Li+ flux.

Flame Retardancy & Thermal Safety: Like other trialkyl/triaryl phosphate esters, the phosphate group (PO4^{3-}-like core) acts as a radical scavenger (capturing H and OH radicals) in the gas phase during thermal abuse. Adding TAP suppresses electrolyte flammability, reduces self-extinguishing time (SET), and decreases volatile gas evolution during high-temperature aging or thermal runaway conditions.

Part Number	CBEATAP (C-BEA-TAP)
CAS	1779-34-6
Chemical Formula	1623-19-4
Appearance	Colorless Liquid
Purity	>99.0% (moisture sensitive)
Molecular Weight	218.19 g/mol
Package Size	5 g, 10 g, and 25 g/bottle

Notes: Please try to store the TAP liquid in a dry place (glovebox is the best)

References: 

1. J. Xia, et al. Study of triallyl phosphate as an electrolyte additive for high voltage lithium-ion cells, Journal of Power Sources, 2015, 295, 203-211.
2. D. Lu, et al. Using Triallyl Phosphate as Electrolyte Additive to Stabilize Electrode–Electrolyte Interface of LiNi0.5Mn1.5O4/Graphite High Voltage Lithium Ion Cells, ACS Appl. Energy Mater. (2022) 5 (11): 13600–13609.