TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide, >99%) as Photoinitiator for Solid-State & Gel Polymer Electrolyte, 100 g/bottle, CSSGPEPITPO

Using TPO (Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide) or its liquid derivative TPO-L (Ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate) as a photoinitiator is an excellent strategy for fabricating gel polymer electrolytes (GPEs) via in situ UV crosslinking. Compared to traditional Norrish Type I initiators like Irgacure 1173 or 2959, TPO offers unique chemical and optical advantages that align perfectly with the strict constraints of battery cell manufacturing.

TPO possesses an absorption tail that extends out into the long-wavelength UV and near-visible blue region (365–420 nm). Standard battery separators (like PP/PE celgard or glass fiber) and concentrated liquid electrolytes often scatter or absorb short-wavelength UV light (sub-300 nm). TPO can achieve rapid, deep through-cure even when curing in situ within a sealed pouch cell or through a semi-opaque separator layer.

Upon UV exposure, TPO undergoes rapid homolytic Norrish Type I cleavage at the C–P bond. This generates two highly reactive radicals: a trimethylbenzoyl radical and a phosphinyl radical. Both radicals are incredibly efficient at initiating the radical polymerization of common GPE monomers like PEGDA (poly(ethylene glycol) diacrylate), ETPTA, or MMA.

Part Number	CSSGPEPITPO (C-SSGPE-PI-TPO)
CAS	75980-60-8
Chemical Formula	(CH3)3C6H2COP(O)(C6H5)2
Appearance	Yellow Powder
Molecular Weight	348.37 g/mol
Melting Point	88-92 °C (lit.)
Package Size	100 g/bottle

Notes: Please try to store the TPO in a dry and dark side.

References: 

1. Q. Wu, et al. Flexible Nanocomposite Polymer Electrolyte Based on UV-Cured Polyurethane Acrylate for Lithium Metal Batteries, ACS Sustainable Chem. Eng. 2021, 9, 16, 5631–5641
2. X. Wang, et al. Application of Polymer Electrolytes Prepared by Ultraviolet Polymerization in Various Lithium Metal Battery Systems, ACS Appl. Energy Mater. 2025, 8, 9, 5564–5584