Combining in situ electrochemistry, operando FTIR and post-mortem analyses to understand Co-Mn-Al spinels on mitigating shuttle effect in lithium-sulfur battery

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Santos, Erick A. ; Anchieta, Chayene G. ; Fernandes, Rodolfo C. ; Pinzon, Manuel J. ; Miranda, Andre N. ; Galantini, Isabela ; Maia, Francisco C. B. ; Doubek, Gustavo ; Rodella, C. B. ; Da Silva, Leonardo M. ; Zanin, Hudson

• Tipo de documento: Artigo Científico
• Fonte: NANO ENERGY; v. 116, p. 15-pg., 2023-08-28.

Resumo

The spinel oxide Co2Mn0.5Al0.5O4 (CMA) was investigated as an additive onto the cathode of lithium-sulfur batteries. We demonstrate the polysulfide adsorption onto CMA, mitigating the shuttle effect, a well-known failure mechanism. The in situ electrochemical impedance spectroscopy and cyclic voltammetry tests evidenced that CMA facilitates the conversion of short-chain lithium polysulfides (LPS). The CMA reduced the maximum voltammetric current by approximately 20% compared to the AC/S cathode and facilitates the conversion of LPS into solid-liquid-solid species. High conversion efficiencies were verified after 315 cycles, resulting in 89% of capacity retention. Low CMA concentrations of up to 10 wt.% increased battery capacity and showed that CMA has high ionic conductivity, while moderate concentrations of approximately 50 wt.% improved cyclability but increased cell's resistivity. This improvement in cyclability is related to LPS trapped at CMA which is demonstrated by micrographs, X-ray energy dispersive and photoelectron spectra of post-mortem samples. The byproducts formed after cycling until failure, were identified by Raman spectra and diffraction patterns. Fourier transform infrared spectroscopy operando analyses suggested electrolyte decomposition as a relevant cell failure mechanism. In conclusion, we demonstrated how CMA can trap LPS and enhanced initial capacity to 1000 mA h g(sulfur)(-1) cm(-2) and improved cyclability for more than similar to 360 cycles. (AU)

• Processo FAPESP: 22/02222-0 - Desenvolvimento de protótipos pouch cells de baterias de lítio-enxofre (Li-S) em estado sólido-líquido com alta estabilidade e avançada escala de maturidade tecnológica
• Beneficiário: Érick Alves Santos
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 20/04281-8 - Proposta de estudo de síntese, caracterização e aplicação de eletrodos para capacitores eletroquímicos tipo bateria de Li-S
• Beneficiário: Érick Alves Santos
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 22/02901-4 - Nano-óptica de poláritons em cristais bidimensionais e na interface metal/dielétrico no infravermelho médio-distante
• Beneficiário: Francisco Carlos Barbosa Maia
• Modalidade de apoio: Auxílio à Pesquisa - Projeto Inicial