Structurally Adaptive Branched Polyimide Binder with Synergistic Elastic Buffering and Ionic Transport for Long-Term Stability of Silicon Anodes.

Overcoming the significant volume expansion and mitigating the poor interfacial stability are pivotal challenges that must be addressed to fully unlock the potential of silicon (Si) as an anode material for next-generation lithium-ion batteries (LIBs). Herein, a 3D branched polyimide binder with superior elasticity and ion conductivity is synthesized through the copolymerization of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) with tough 4,4'-oxydianiline (ODA), polar isophthalic dihydrazide (IDP), and flexible poly(dimethylsiloxane)etherimide (DMS), while incorporating branched 1,3,5-tris(4-aminophenoxy)benzene (TAPOB) to construct a robust 3D crosslinked network. The 3D network of mPI-T contains abundant aromatic benzene rings, providing high toughness and structural stability.

Separator Engineering Regulating Reversible Li Electrodeposition Enabled by Lithiophilic Polyimide@Ag Coating Layer for Dendrite-Free Lithium Metal Batteries.

Heterogeneity Li deposition predominantly induce the growth of Li dendrite, which hinders the practical application of lithium metal batteries (LMBs). Previous researches have mainly focused on the modification of lithium anode, but lithium is sensitive to water and oxygen, which consequently limits its industrialization process. Herein, a novel polyimide@Ag coated polyethylene separator ((PI@Ag)/PE)  strategy is reported to inhibit Li dendrites growth.

Three-Dimensional Fluorescent Imaging to Identify Multi-Paths in Polymer Aging.

It is of great significance to disclose the diverse aging pathways for polymers under multiple factors, so as to predict and control the potential aging evolution. However, the current methods fail to distinguish multiple pathways (multi-paths) of polymer aging due to the lack of spatiotemporal resolution. In this work, using polyimide as a model polymer, the hydroxyl, carboxyl, and amino groups from the polyimide aging process were labeled using specific fluorescent probes through boron-oxygen, imine, and thiourea linkages, respectively.

Structural Evolution of Macromolecular Chain During Pre-imidization Process and Its Effects on Polyimide Film Properties.

Pre-imidization has been found to have a determining role on the final properties of polyimide (PI) films. In this work, a series of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA)/2,2'-bis(trifluoromethyl)benzidine (TFMB) PI models with specified pre-imidization degree (pre-ID) were constructed and analyzed on the basis of molecular dynamic (MD) simulation to reveal the real-time evolution of structure and properties that occurred during the pre-imidization process. The MD results indicated that the of the models increased obviously with increasing pre-ID, which corresponded to the increase of rigid PI chain segments that restricted the mobility of molecular chains.