At battery facets, solar interfaces and solvent benches, small surfaces decide performance

Lithium balance at the cathode facet

In a preprint posted to ChemRxiv, researchers examine textured lithium cobalt oxide battery electrodes and find that performance depends less on bulk composition than on lithium balance at fast-diffusing facets. Lithium-balanced textured electrodes suppress kinetically driven degradation pathways at (110) terminating facets. That balance is the central result: the same electrode material behaves differently depending on whether lithium content at the surface is held near balance, pushed low, or pushed high. m:…3592

The two failure modes reported in the preprint are distinct, which is why a single fix is unlikely to cover both. Lithium-poor textured cathodes show accelerated interfacial degradation through rapid rocksalt formation. Lithium-rich textured electrodes show elevated interfacial degradation through formation of poorly conducting lithium carbonate. The authors present precise control of lithium stoichiometry as a route to cathodes with better cycle life and surface stability. The practical implication is that electrode design must control the facet interface, not only the average lithium content of the material. m:…3592

Traps in the solar transport layer

In a second preprint posted to ChemRxiv, the vulnerable interface sits in a perovskite solar cell, in the fullerene electron transport layer. Mobile halide species generated during perovskite fabrication and passivation, including iodide, iodine and polyiodides, form deep electron traps in C60 transport layers. Those traps interfere with charge extraction, so a cell can lose performance even when its light-absorbing layer is sound. The problem is created in part by steps meant to help: ammonium halide surface passivation treatments can cause performance losses within 30 minutes of operation. m:…9760

Fabrication route changes how exposed a device is to that damage. Two-step vapor-deposited perovskites exhibit higher sensitivity to air-induced performance losses compared with spin-coated perovskites. That comparison gives device engineers a concrete variable to control, alongside passivation chemistry and transport layer choice. It also shows why stability testing must track the interface over operating time, since a treatment that looks helpful at fabrication can turn into a trap-forming step once the device runs. m:…9760

Carbon capture solvents need bench checks

In a third preprint posted to ChemRxiv, researchers test an iterative workflow for finding deep eutectic solvents for carbon dioxide capture, combining COSMO-RS computational screening with experimental solid-liquid equilibrium validation. The screening step is effective at identifying promising candidates and reducing experimental effort. But the preprint stresses that screening alone is not enough, because computational prediction can overstate stability and miss decomposition and metastable behaviour that only bench testing reveals. m:…2998

The contrast between two candidate systems makes the point. One system, based on betaine and triethanolamine, forms a stable liquid phase suitable for carbon dioxide capture applications. Another system, based on betaine and monoethanolamine, was predicted to be liquid at ambient conditions but decomposes experimentally and fails to form a stable liquid phase. A third system, based on L-tryptophan and monoethanolamine, shows a liquidus temperature prediction error of approximately 2 kelvin, which sits within the 3 kelvin experimental uncertainty. The workflow therefore works best as a filter followed by a check, not as a replacement for the check. m:…2998

Recycled oils and the limits of current analysis

In a fourth preprint posted to ChemRxiv, a systematic review of 96 studies examines plastic pyrolysis oils as steam cracker feedstocks, a chemical recycling route rather than a battery or carbon capture process, but one governed by the same interface problem. Untreated pyrolysis oil and naphtha blends result in a 2.4-fold increase in coke formation compared with standard naphtha, an operational risk for cracker reliability. Current gas chromatography-based analytical methods account for approximately 11 percent of total silicon content, leaving most silicon unassigned by that route. Olefin estimates for the oils vary by 7.4 percentage points across existing literature despite high pooled correlation coefficients. m:…5954

The authors present the review as a framework for standardising feed qualification, so that industrial operating reliability does not rest on incomplete analysis. The gap is practical: if coking risk and contaminant content cannot be measured consistently, a feedstock that looks acceptable on paper can still foul equipment in operation. That lesson echoes the battery and solar findings. In each case, bulk averages hide the small-scale behaviour that determines whether a material survives real use. m:…5954

The shared lesson

Across all four preprints, progress is decided at facets, transport layers, solvent phases and feedstock interfaces, not by headline composition alone. Lithium balance protects a cathode facet, halide control protects a solar transport layer, experimental validation protects a solvent choice, and fuller analysis protects a recycling feedstock. Each study also leaves its next test open: cycle life at scale for balanced cathodes, operating lifetime for trap-resistant solar cells, capture performance under real conditions for validated solvents, and a qualification standard that plants can apply to recycled oils. The common thread is modest and useful. Measure the interface, test it under operating conditions, and do not trust a bulk number to stand in for either. m:…3592 m:…9760 m:…2998 m:…5954