Deconstructing solid-state batteries (SSBs) to physically separated cathode and solid-electrolyte particles remains intensive, as does the remanufacturing of cathodes and separators from the recovered materials. To address this challenge, we designed supramolecular organo-ionic (ORION) electrolytes that are viscoelastic solids at battery operating temperatures (-40° to 45°C) yet are viscoelastic liquids above 100°C, which enables both the fabrication of high-quality SSBs and the recycling of their cathodes at end of life. SSBs implementing ORION electrolytes alongside Li metal anodes and either LFP or NMC cathodes were operated for hundreds of cycles at 45°C with less than 20% capacity fade. Using a low-temperature solvent process, we isolated the cathode from the electrolyte and demonstrated that refurbished cells recover 90% of their initial capacity and sustain it for an additional 100 cycles with 84% capacity retention in their second life.

Proton-exchange membrane fuel cells (PEMFCs) are promising energy-conversion systems, offering an appealing blend of high energy efficiency and low environmental impact. However, carbon corrosion of PEMFCs is known to significantly degrade their performance, remaining a critical challenge to overcome. In this study, we applied a Nb-doped SnO2 (Nb-SnO2) nanoparticle coating on Pt/C catalysts as a protective layer, with the Sn/C ratio in the precursors varying from 0.25:1 to 2.0:1. Contradictory behaviors of the coated Pt/C catalysts were observed at different Sn/C ratios. The Sn/C = 1.0 sample exhibited improved electrochemically active surface area retention after 500 cycles of accelerated stress testing (AST) but with more significant polarization and resistance increase observed in the polarization curves. In addition, agglomeration of Nb-SnO2 particles was observed at a higher Sn/C ratio in the AST of a membrane electrode assembly, with less shrinkage of the total thickness of the Nb-SnO2-coated Pt/C electrode. We speculate that formation of Nb-SnO2 agglomerates occurs once the protective layer is broken down or the unprotected carbon surface is corroded and that these Nb-SnO2 agglomerates increase the tortuosity of the electron pathways and significantly increase the cell polarization.

A composite structure was developed for use in all-solid-state batteries that consists of a conductive 3D reduced graphene oxide framework embedded beneath cathode active material particles. This unique structure offers significant advantages when combined with a sulfide solid electrolyte as the heterogeneous distribution of the conductive carbon in the composite cathode ensures good contact between the carbon and cathode particles for facile electron transfer while a direct contact between the carbon and sulfide solid electrolyte is avoided or minimized. This approach assists in preventing or reducing unwanted irreversible faradaic reactions. As a result, the newly developed composite of cathode particles decorated on a 3D reduced graphene oxide framework delivers higher specific capacity with improved cycling stability compared with a typical composite cathode consisting of a homogenous mixture of the cathode active material, carbon nanofibers, and sulfide solid electrolyte.

The success of solid-state synthesis often hinges on the first intermediate phase that forms, which determines the remaining driving force to produce the desired target material. Recent work suggests that when reaction energies are large, thermodynamics primarily dictates the initial product formed, regardless of reactant stoichiometry. Here, we validate this principle and quantify its constraints by performing in situ characterization on 37 pairs of reactants. These experiments reveal a threshold for thermodynamic control in solid-state reactions, whereby initial product formation can be predicted when its driving force exceeds that of all other competing phases by ≥60 milli-electron volt per atom. In contrast, when multiple phases have a comparable driving force to form, the initial product is more often determined by kinetic factors. Analysis of the Materials Project data shows that 15% of possible reactions fall within the regime of thermodynamic control, highlighting the opportunity to predict synthesis pathways from first principles.