Pyrrolidinium-Based Organic Cation (BMP)-Intercalated Organic (Coronene) Anode for High-Voltage Dual-Ion Batteries: A Comparative Study with Graphite

Abstract

Among the post-lithium-ion batteries, rechargeable dual-ion batteries (DIBs) have bright opportunities for the development of cheap and safe batteries possessing a good electrochemical performance. The DIBs with pure ionic liquid (IL) electrolytes featuring a high voltage, sustainability, and environmental friendliness have received attention from researchers. Owing to intercalation/deintercalation of large size IL cations, the conventional dual-graphite batteries (DGBs) have suffered from severe volume expansion, thus limiting the overall reversibility of the DGBs. Herein, we have modeled two DIBs, introducing an organic cation-intercalated polycyclic aromatic hydrocarbon anode (coronene) coupled with a graphite cathode and a DGB in the other case. Pyrrolidinium-based IL, N-butyl-N-methyl pyrrolidinium chloride (BMP-Cl) with the AlCl3 salt has been employed as an electrolyte. Applying the first-principles calculation, we have investigated the systematic intercalation of the BMP cation into the coronene and graphite anodes. The BMP-intercalated graphite anode shows a higher binding energy (2.36 eV) compared to that of the coronene anode (1.71 eV). In the fully charged state, a calculated discharge voltage of 3.1 and 3.05 V and a maximum capacity of 116 and 130 mA h g–1 have been observed for the graphite coronene dual-ion battery (GCDIB) and DGB, respectively. However, the percentage of volume expansion of the graphite anode is higher (148%) compared to that of the coronene anode (53%) upon a full intercalation of BMP cations, indicating more exfoliation-prone nature of graphite compared to coronene. The density of states and Bader charge analysis reveal that the BMP cation is intercalated successfully, indicating a reduction of electrode materials during the charging process. Furthermore, we have explained the merits of choosing the AlCl4 anion compared to other commonly used anions such as TFSI in DIBs. These results support a clear understanding of BMP cation intercalation into both coronene and graphite anodes and motivate the fabrication of a new class of low-cost organic anode DIBs with an optimum electrochemical performance.

Recent Advancements in Devising Computational Strategies for Dual‐Ion Batteries

“…On the contrary, the intercalation of cationic species induces charge transfer to the electrode. In such a case, the electronic states are stabilized, and the Fermi level shifts towards the conduction bands [27] . Consequently, the electrode is reduced.…”

“…The aromatic DMPI cation intercalation/deintercalation processes are to some extent irreversible because of the strong π–π interaction of imidazolium ring and graphite layers, and huge volume expansion of the graphite layers result in the diminishing of overall cycle life. To overcome these issues, we have considered a coronene‐based PAH anode, which already has enough space to host the intercalant and graphite cathode with non‐aromatic pyrrolidinium‐based BMP‐AlCl 4 IL electrolyte [27] . The graphite‐coronene DIB (GCDIB) has shown better electrochemical performance compared to the DGBs.…”

“…Cations and anions of the ILs can also be intercalated into the host materials, though limited study has been observed on this concept both experimentally and computationally [25,27,70–72] . In general, carbonaceous host materials such as graphite and polycyclic aromatic hydrocarbons (PAHs) are used as electrodes, which have enough space to accommodate the large size cations and anions of ILs [50] .…”

“…Cations and anions of the ILs can also be intercalated into the host materials, though limited study has been observed on this concept both experimentally and computationally. [25,27,[70][71][72] In general, carbonaceous host materials such as graphite and polycyclic aromatic hydrocarbons (PAHs) are used as electrodes, which have enough space to accommodate the large size cations and anions of ILs. [50] We have conceptually demonstrated the dual graphite battery (DGB) with DMPI-AlCl 4 ionic liquid electrolyte, upon mixing of 1 : 1 ratio of 1,2-dimethyl-3propyl imidazolium chloride (DMPIÀ Cl) and AlCl 3 salt.…”

“…In such a case, the electronic states are stabilized, and the Fermi level shifts towards the conduction bands. [27] Consequently, the electrode ChemSusChem is reduced. These changes in electronic structure of an electrode material are important to understand whether the material is suitable for cation or anion binding.…”