TMO {(2,4,6-trimethyl-benzoyl)bis(p-tolyl)phosphine oxide, >99%} as Photoinitiator for Solid-State & Gel Polymer Electrolyte, 100 g/bottle, CSSGPEPITMO

Photoinitiator TMO—chemically (2,4,6-trimethylbenzoyl)bis(p-tolyl)phosphine oxide (CAS 270586-78-2)—has rapidly emerged as the premier alternative to traditional TPO for synthesizing gel polymer electrolytes (GPEs) via ultraviolet (UV) curing.

Excellent LED Compatibility & Deep Curing: The emission bands of modern UV-LED curing setups are highly concentrated at 365 nm, 385 nm, 395 nm, and 405 nm. Like TPO, TMO is an acylphosphine oxide (Type I free radical) photoinitiator that exhibits excellent absorption in the UV-A and near-visible blue light regions.  This long-wavelength absorption ensures high penetration depth. In thick or highly filled composite polymer electrolyte matrices (e.g., those containing ceramic fillers like oxide or sulfide solid electrolytes), TMO ensures complete conversion of the acrylic double bonds (C=C) without leaving uncured, liquid-like dead zones. 

High Initiation Efficiency & Fast Crosslinking: Double-bond conversion kinetics show that TMO exhibits initiation efficiency that is equal to or slightly better than TPO.  It enables rapid crosslinking (often under 30–60 seconds) of common GPE monomers like poly(ethylene glycol) diacrylate (PEGDA), ethoxylated trimethylolpropane triacrylate (ETMPTA), or dipentaerythritol hexaacrylate (DPHA).

Benzene-Free & Low Migration (Electrochemical Stability): Traditional photoinitiators can release benzene fragments or other volatile, low-molecular-weight byproducts during decomposition. These impurities can migrate to the electrode interfaces and undergo parasitic electrochemical oxidation or reduction, compromising the solid electrolyte interphase (SEI) or cathode electrolyte interphase (CEI). TMO features p-tolyl groups (introducing a methyl group onto each of the benzene rings of TPO), which dramatically reduces toxicity, suppresses migration out of the cured polymer network, and improves structural stability inside the cell environment.

Part Number	CSSGPEPITMO (C-SSGPE-PI-TMO)
CAS	270586-78-2
Chemical Formula	C₂₄H₂₅O₂P
Appearance	Yellow Powder
Purity	>99.0%
Molecular Weight	376.43 g/mol
Melting Point	~126°C to 131°C
Package Size	100 g/bottle

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

References: 

1. H. Tsutsumi, et al. Cross-linked poly(oxetane) matrix for polymer electrolyte containing lithium ions, Solid State Ionics, 2014, 262, 761-764
2. T. Shuai, et al. Electrolyte Evolution for Flexible Energy Storage Systems: From Liquid to Solid, from Rigid to Soft, and from Organic to Aqueous, Chem. Rev. 2025, 125, 15, 7167–7222