Microbe-Assisted Nanocomposite Anodes for Aqueous Li-Ion Batteries

Abstract

With the rapid increase in the use of lithium-ion batteries (LIBs), the development of safe LIBs has become an important social issue. Replacing flammable organic liquid electrolytes in current LIBs with water can be an alternative route to resolve this safety concern. The waterin-salt (WIS) electrolytes received great attention as next-generation electrolytes due to their large electrochemical stability window. However, their high cathodic limit remains as a challenge, impeding the use of lowpotential anodes. Here, we report the first biodirected synthesis of carbonaceous layers on anodes to use them as interlayers that prevent a direct contact of water molecules to anode particles. Highaspect ratio microbes are utilized as precursors of carbonaceous layers on TiO 2 nanoparticles (m-TiO 2 ) to enhance the conductivity and to reduce the electrolysis of WIS electrolytes. We selected the cylindrical shape of microbes that offers geometric diversity, providing us a toolkit to investigate the effect of microbe length in forming the network in binary composites and their impacts on the battery performance with WIS electrolytes. Using microbes with varying aspect ratios, the optimal microbe size to maximize the battery performance is determined. The effects of storage time on microbe size are also studied. Compared to uncoated TiO 2 anodes, m-TiO 2 exhibited 49% higher capacity at the 40th cycle and enhanced the cycle life close to anodes made with a conventional carbon precursor while using an 11% less amount of carbon. We performed density functional theory calculations to unravel the underlying mechanism of the performance improvement using microbe-derived carbon layers. Computational results show that high amounts of pyridinic nitrogen present in the peptide bonds in microbes are expected to slow down the water diffusion. Our findings provide key insights into the design of an interlayer for WIS anodes and open an avenue to fabricate energy storage materials using biomaterials.

Bifunctional Al2O3-Based Artificial Layers on LiNiO2 Cathodes for High-Energy-Density Aqueous Li-Ion Batteries

“…Aqueous lithium-ion batteries (ALIBs) that use aqueous solutions as electrolytes are often regarded as promising alternatives to lithium-ion batteries (LIBs) due to their advantageous characteristics, such as their low cost, affordability, environmental friendliness, and higher level of safety. − Since the first report by Dahn et al, various studies on ALIBs have been conducted with a surge in the number of publications. However, their low energy densities, attributed to the subpar electrochemical characteristics of the electrode materials in aqueous electrolytes and the narrow potential windows of these electrolytes, still limit their practical application in commercial devices such as electric vehicles.…”

Regeneration of Electrocatalyst through Li-Ion Insertion

“…[11][12][13][14] Different phases including Li 0.05 to 0,1 TiO 2 or Li ε TiO 2 (α), Li-titanate Imma (β) phase or Li 0.55 TiO 2 and the tetragonal LiTiO 2 I41/amd (γ) phase have been identified depending on the crystallite size and the potential range. It has also been reported a few times in aqueous batteries in superconcentrated electrolytes, 15,16 and reducing hydrogen generation to allow the formation of a protective Solid Electrolyte Interphase (SEI) was challenging. The photo(electro)catalytic properties of anatase TiO 2 have been widely explored, 17,18 the ones of lithiated TiO 2 towards Oxygen Evolution Reaction (OER) have been considered 19,20 ; the catalytic HER properties of TiO 2 have been studied, 21 however the ones of lithiated TiO 2 remains unexplored.…”