# Metastable π‐Lithium Supermolecule Entities Govern Voltage in Electron‐Rich Electrolytes: Orbital Energetics as Predictive Voltage Descriptors

## TL;DR

This paper explains how specific molecular structures in lithium solutions control voltage, enabling better design of high-performance batteries.

## Contribution

The study identifies a new class of lithium supermolecules and establishes a predictive voltage model based on molecular orbital energies.

## Key findings

- Lithium supermolecules (SMEs) modulate voltage through push-pull interactions involving PAHs, Li⁺, and tetrahydrofuran.
- Open-circuit voltage (OCV) correlates strongly with the lowest unoccupied molecular orbital (LUMO) energy of PAHs.
- A high-throughput screening strategy using PAH LUMO energy enables rapid identification of high-voltage electrolyte additives.

## Abstract

Lithium‐solvated‐electron solutions (Li‐SESs) hold immense promise as transformative, high energy‐storage media for applications such as liquid batteries and anode prelithiation. However, their fundamental architectures and intrinsic voltage regulation mechanisms remain incompletely understood. Through ab initio molecular dynamics simulations, we find a novel class of electroactive Lithium‐p supermolecule entities (SMEs), which serve as key voltage‐modulating components. These SMEs form through synergistic aggregation of polycyclic aromatic hydrocarbons (PAHs), Li+, solvated‐electrons, and tetrahydrofuran where PAHs function as π‐scaffolds through hyperconjugation‐driven push‐pull interactions. We establish a robust open‐circuit voltage (OCV) computation model demonstrating strong linear correlations across 8 PAH‐Li‐SESs (R2〉0.96). Crucially, OCV correlates with the highest‐occupied‐molecular‐orbital energy of SME, intrinsically linked to the lowest‐unoccupied‐molecular‐orbital (LUMO) energy of PAH molecule, enabling a predictive PAH‐LUMO‐to‐OCV relationship. This dual‐descriptor framework achieves quantitative OCV predictions for 23 PAHs (including 15 previously unexplored systems), validated against experimental data. PAHs with LUMO‐energy〈 ‐2.0 eV consistently yield OCV 〉 900 mV, enabling rational design of high‐voltage anolytes. Consequently, we develop a high‐through put screening strategy using PAH LUMO‐energy to rapidly identify additives for high‐voltage Li‐SESs and electron‐rich electrolytes. Overall, this SME‐framework facilitates rational additive engineering for high‐voltage alkali‐metal SES anolytes and optimized prelithiation reagents, significantly accelerating advanced electrolyte development.

Solvated electron supermolecules (SMEs) formed by polycyclic aromatic hydrocarbon (PAH), Li⁺, and tetrahydrofuranmodulate voltage in lithium solutions. The open‐circuit‐voltage (OCV) of such solutions correlates with the lowest unoccupied molecular orbital energy of PAH, enabling high‐throughput screening for high‐voltage electrolytes. This framework supports rational design of high‐performance anolytes and prelithiation reagents.