BPEI {Branched Poly(ethyleneimine)} Liquid as Battery Electrode Binder, 50 g/bottle, CBEBBPEI

Poly(ethyleneimine) is a bifunctional material that provides both mechanical adhesion and active chemical stabilization. It has two forms: Linear PEI (LPEI) and Branched PEI (BPEI), with the branched version being especially useful for creating 3D cross-linked networks. PEI is perhaps most famous as a binder for Lithium-Sulfur (Li-S) batteries since (1) The primary, secondary, and tertiary amine groups in PEI have a very strong chemical affinity for lithium polysulfides; (2) The nitrogen atoms in the PEI chain act as strong nucleophilic sites that chemically bind and immobilize polysulfides at the cathode. This significantly suppresses the "shuttle effect," which is the leading cause of capacity loss in Li-S systems.

Moreover, PEI is often used as a macromolecular cross-linker rather than a standalone binder. One of the most researched combinations is Poly(acrylic acid) (PAA) mixed with PEI. The carboxylic groups of PAA and the amino groups of PEI form strong ionic and covalent bonds (amide bonds). This creates a robust, 3D cross-linked network that is far more effective than linear binders at "caging" silicon particles. It maintains the electrical network even when silicon undergoes its massive 300% volume expansion.

Part Number	CBEBBPEI (C-BEB-BPEI)
CAS	9002-98-6
Chemical Formula/Structure	Branched PEI
Appearance	Colorless liquid (If customer need the aqueous BPEI dispersion (35 wt%, 1300 cP, we can provide it upon request)
Package Size	50 g/bottle

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

References: 

1. C. Chen, et al. Cross-linked hyperbranched polyethylenimine as an efficient multidimensional binder for silicon anodes in lithium-ion batteries, Electrochimica Acta, 2019, 326, 134964.
2. H. S. Jeong, et al. Novel Anchored Branched Polymer Coating Layers for Enhanced Redox Kinetics in Aqueous Zinc-Ion Batteries, Energy Environ. Mater., 2025, 8, e12872.