Stable silicon-ionic liquid interface for next-generation lithium-ion batteries

Abstract

We are currently in the midst of a race to discover and develop new battery materials capable of providing high energy-density at low cost. By combining a high-performance Si electrode architecture with a room temperature ionic liquid electrolyte, here we demonstrate a highly energy-dense lithium-ion cell with an impressively long cycling life, maintaining over 75% capacity after 500 cycles. Such high performance is enabled by a stable half-cell coulombic efficiency of 99.97%, averaged over the first 200 cycles. Equally as significant, our detailed characterization elucidates the previously convoluted mechanisms of the solid-electrolyte interphase on Si electrodes. We provide a theoretical simulation to model the interface and microstructural-compositional analyses that confirm our theoretical predictions and allow us to visualize the precise location and constitution of various interfacial components. This work provides new science related to the interfacial stability of Si-based materials while granting positive exposure to ionic liquid electrochemistry.

Electrospun polyacrylonitrile microfiber separators for ionic liquid electrolytes in Li-ion batteries

“…Composite electrodes were fabricated using slurry coating of Li(Ni 1/3 Mn 1/3 Co 1/ 12 h prior to fabrication of full-cells. Full-cells were built and tested according to the procedure outlined in our previous work, in which each electrode were electrochemically pre-conditioned prior to placing in the full-cell to allow precise control of the amount of lithium in the system [24]. Calculated from the active material mass, nSi-cPAN anodes were fabricated and matched with L333 cathodes such that the total anode capacity was 160% of that of the cathode capacity.…”

Design of an ultra-durable silicon-based battery anode material with exceptional high-temperature cycling stability

“…Electrolyte depletion can be accelerated when lithium alloying elements are used as anode materials. These elements (Si, Ge, Sn, and Pb) have high theoretical capacities, but higher temperatures generally react with more lithium ions, resulting in extremely large volume changes ( 4300%), severe cracking of the original structure, and formation of a thick solid-electrolyte-interface (SEI) layer [5][6][7][8]. Of the lithium alloying elements, Si is seen as a key material for next-generation LIBs because of its high theoretical capacity (3579 mA h g À 1 at room temperature), low reaction potential (o0.4 V vs. Li/Li þ ), natural abundance, and low cost [9,10].…”

Communication: Nanoscale structure of tetradecyltrihexylphosphonium based ionic liquids

“…Instead, upon a temperature increase, the apolar subcomponents contribute to what would be an expected decrease of prepeak intensity. C Ongoing research on ionic liquids (ILs) continues to grow due to numerous possible applications including CO 2 capture, 1-13 energy storage, [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and cellulose processing.…”