FeS₂ cathode is promising for all-solid-state lithium batteries due to its ultra-high capacity, low cost, and environmental friendliness. However, the poor performances, induced by limited electrode-electrolyte interface, severe volume expansion, and polysulfide shuttle, hinder the application of FeS₂ in all-solid-state lithium batteries. Herein, an integrated 3D FeS₂ electrode with full infiltration of Li₆PS₅Cl sulfide electrolytes is designed to address these challenges. Such a 3D integrated design not only achieves intimate and maximized interfacial contact between electrode and sulfide electrolytes, but also effectively buffers the inner volume change of FeS₂ and completely eliminates the polysulfide shuttle through direct solid–solid conversion of Li₂S/S. Besides, the vertical 3D arrays guarantee direct electron transport channels and horizontally shortened ion diffusion paths, endowing the integrated electrode with a remarkably reduced interfacial impedance and enhanced reaction kinetics. Benefiting from these synergies, the integrated all-solid-state lithium battery exhibits the largest reversible capacity (667 mAh g⁻¹), best rate performance, and highest capacity retention of 82% over 500 cycles at 0.1 C compared to both a liquid battery and non-integrated all-solid-state lithium battery. The cycling performance is among the best reported for FeS₂-based all-solid-state lithium batteries. This work presents an innovative synergistic strategy for designing long-cycling high-energy all-solid-state lithium batteries, which can be readily applied to other battery systems, such as lithium-sulfur batteries.

Low electrolyte/sulfur ratio (E/S) is an important factor in increasing the energy density of lithium-sulfur batteries (LSBs). Recently, the E/S has been widely lowered using catalytic hosts that can suppress “shuttle effect” during cycling by relying on a limited adsorption area. However, the shelf-lives of these cathodes have not yet received attention. Herein, we show that the self-discharge of sulfur cathodes based on frequently-used catalytic hosts is serious under low E/S because the “shuttle effect” during storage process caused by polysulfides (PSs) disproportionation cannot be suppressed using a limited adsorption area. We further prove that the adsorption strength toward PSs, which is unfortunately weak in commonly-used catalytic hosts, is critical for effectively hindering the disproportionation of the PSs. Subsequently, to verify this conclusion, we prepare a sulfur-doped titanium nitride (S-TiN) catalytic array host. As the adsorption strength and catalytic activity of TiN can be improved by S doping simultaneously, the constructed S/S-TiN cathodes under a low E/S (6.5 μL·mg⁻¹) exhibit better shelf-life and cycle-stability than those of S/TiN cathodes. Our work suggests that enhancing the adsorption strength of catalytic hosts, while maintaining their function to reduce E/S, is crucial for practical LSBs.