Sparsely Pillared Graphene Materials for High-Performance Supercapacitors: Improving Ion Transport and Storage Capacity

Harish Banda (1) , Sandy Périé (2) , Barbara Daffos (3) , Pierre-Louis Taberna (3) , Lionel Dubois (2) , Olivier Crosnier (4) , Patrice Simon (3) , Daniel Lee (5) , Gaël de Paëpe (5) , Florence Duclairoir (2)

1 SYMMES - SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé
2 CAMPE - Conception d’Architectures Moléculaires et Processus Electroniques
3 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
4 IMN - Institut des Matériaux Jean Rouxel
5 RM - Magnetic Resonance

Graphene-based materials are extensively studied as promising candidates for supercapacitors (SCs) owing to the high surface area, electrical conductivity, and mechanical flexibility of graphene. Reduced graphene oxide (RGO), a close graphene-like material studied for SCs, offers limited specific capacitances (100 F·g–1) as the reduced graphene sheets partially restack through π–π interactions. This paper presents pillared graphene materials designed to minimize such graphitic restacking by cross-linking the graphene sheets with a bifunctional pillar molecule. Solid-state NMR, X-ray diffraction, and electrochemical analyses reveal that the synthesized materials possess covalently cross-linked graphene galleries that offer additional sites for ion sorption in SCs. Indeed, high specific capacitances in SCs are observed for the graphene materials synthesized with an optimized number of pillars. Specifically, the straightforward synthesis of a graphene hydrogel containing pillared structures and an interconnected porous network delivered a material with gravimetric capacitances two times greater than that of RGO (200 F·g–1vs 107 F·g–1) and volumetric capacitances that are nearly four times larger (210 F·cm–3vs 54 F·cm–3). Additionally, despite the presence of pillars inside the graphene galleries, the optimized materials show efficient ion transport characteristics. This work therefore brings perspectives for the next generation of high-performance SCs.

Mots clés: Pillared graphene; Ion sieving; Graphene hydrogel; Interlayer galleries; Supercapacitors

Domaines: Matériaux; Energie électrique

Harish Banda, Sandy Périé, Barbara Daffos, Pierre-Louis Taberna, Lionel Dubois, et al.. Sparsely Pillared Graphene Materials for High-Performance Supercapacitors: Improving Ion Transport and Storage Capacity. ACS Nano, 2019, 13 (2), pp.1443-1453. ⟨10.1021/acsnano.8b07102⟩. ⟨hal-02079872⟩