Electron/ion-conductive flexible copolymer PEDOT-PDMS (poly(3,4-ethylenedioxythiophene)-poly(dimethylsiloxane)) was successfully developed, which not only effectively optimizes high-voltage NaLiFePO₄F cathode through dripping on electrode surface but also improves high-capacity Si anode through in-situ polymerization on the surface of Si particles. Theoretical calculation and experiments indicate that π-π conjugated structure in PEDOT-PDMS molecular chains easily interacts with PF₆^– anions, providing electron transfer pathways and preventing HF production. Moreover, Li ions transfer through Si-O in the amorphous phase of the copolymer, and its Young’s modulus at rupture is 1.17±0.10 MPa. The in-situ TEM results directly confirm that the polymer layer provides conducting pathways and buffers the stress induced by lithiation. With the NaLiFePO₄F coated cathode, the cells show good cycle stability (~100% of capacity retention after 500 cycles) and high chemical diffusion coefficient of lithium-ions (1.89×10^–9 cm²·s^–1 and 1.20×10^–9 cm²·s^–1). In the case of coated Si anode, a capacity of 1512 mAh·g^–1 is retained after 1000 cycles at 0.5 C with a capacity retention of 69.8% in terms of the highest specific capacity around the 160^th cycle. This work opens a new avenue for the simultaneous optimization of cathode and anode with a functional polymer.

Since lithium sulfur (Li-S) energy storage devices are anticipated to power portable gadgets and electric vehicles owing to their high energy density (2600 Wh·kg^–1); nevertheless, their usefulness is constrained by sluggish sulfur reaction kinetics and soluble lithium polysulfide (LPS) shuttling effects. High electrically conductive bifunctional electrocatalysts are urgently needed for Li-S batteries, and high-entropy oxide (HEO) is one of the most promising electrocatalysts. In this work, we synthesize titanium-containing high entropy oxide (Ti-HEO) (TiFeNiCoMg)O with enhanced electrical conductivity through calcining metal-organic frameworks (MOF) templates at modest temperatures. The resulting single-phase Ti-HEO with high conductivity could facilitate chemical immobilization and rapid bidirectional conversion of LPS. As a result, the Ti-HEO/S/KB cathode (with 70 wt.% of sulfur) achieves an initial discharge capacity as high as ~1375 mAh·g^–1 at 0.1 C, and a low-capacity fade rate of 0.056% per cycle over 1000 cycles at 0.5 C. With increased sulfur loading (~5.0 mg·cm^–2), the typical Li-S cell delivered a high initial discharge capacity of ~607 mAh·g^–1 at 0.2 C and showcased good cycling stability. This work provides better insight into the synthesis of catalytic Ti-containing HEOs with enhanced electrical conductivity, which are effective in simultaneously enhancing the LPS-conversion kinetics and reducing the LPS shuttling effect.