Synergistic bifunctional conjugated microporous polymer as an organic anode containing tetraphenylethene and thianthrene-5,5′,10,10′-tetraoxide units for lithium and sodium-ion batteries

Abstract

This study reports the synthesis and an early exploration of the electrochemical investigation of a donor–π–acceptor (D–π–A) conjugated microporous polymer (CMP), TPEHBZ-ThBS, incorporating tetraphenylethene and thianthrene-5,5′,10,10′-tetraoxide units for reversible Li⁺/Na⁺ storage. Potentially scalable and sustainable TPEHBZ-ThBS CMP is synthesized via Suzuki coupling of 2,8-dibromothianthrene-5,5′,10,10′-tetraoxide (ThBS-Br₂), 1,1,2,2-tetrakis(4-bromophenyl)ethene (TPEH-Br₄), and 1,4-phenylenediboronic acid, and its structure is confirmed through comprehensive characterization. Electrochemical testing in CR-2032 coin cells reveals discharge capacities of 410 mAh g⁻¹ (LIB) and 260 mAh g⁻¹ (SIB) at 0.1C. Additionally, the lithium-ion full cell using NMC811 as the cathode and TPEHBZ-ThBS CMP as the anode exhibits a discharge capacity of 122 mAh g⁻¹ at 0.1C-rate. Dunn's method and power-law analysis indicate a hybrid charge storage mechanism, dominated by diffusion-controlled processes. The sulfonyl groups facilitate strong Li⁺/Na⁺ binding, promoting efficient charge transport. The high redox activity, stable structure, and fully conjugated backbone collectively contribute to the capacity, rate performance, and cycling stability of the CMP, underscoring its potential for advanced energy storage applications.