Mechanism of a Lithiated Interlayer for Improving the Cycle Life of High Voltage Li-Ion Batteries Using a Commercial Carbonate Electrolyte

Abstract

The high voltage (5 V class) Li-ion batteries with spinel LiNi0.5Mn1.5O4 (LNMO), olivine LiCoPO4, or layer–layer composite xLi2MnO3·(1 – x)­LiMnO2 as a cathode and carbon (e.g., graphite) as an anode are expected to become a new generation of high energy density batteries. However, the cycle stability of these batteries is very poor because a stable cathode–electrolyte interface (CEI) layer cannot be formed in a commercial carbonate electrolyte at such a high voltage, and then the electrolyte oxidation products from the cathode cause the anodes to fail. In this work, taking LNMO/graphite full cell as the representative, the effect of Li metal and lithiated LNMO interlayers on the cycling behavior of the cell is studied. It is found that both interlayers can greatly improve the cycle life of the full cell, because they can consume and block the electrolyte oxidation products from the LNMO cathode, thus protecting the graphite anode from being destroyed. The optimum reduction activity range of a lithiated interlayer is 0.75–2.0 V (vs Li+/Li) for the 5 V class Li-ion batteries because the interlayer with excessive reductivity (<0.75 V) can reduce and decompose the electrolyte itself.

Long-Term Cycling of a Mn-Rich High-Voltage Spinel Cathode by Stabilizing the Surface with a Small Dose of Iron

“…As shown, an excellent performance with a capacity retention of ∼90% is achieved after 300 cycles. This is one of the best performances ever reported at such a high mass loading for the high-voltage LNMO spinel. ,− The CEs are plotted in Figure b; the cell exhibits an average CE of 99.45%, implying that the lithium inventory loss is suppressed. Notably, the cell impedance growth is negligible, as depicted in Figure c.…”

Investigation of performance of cobalt oxide (CoO) and titanium dioxide (TiO2) attached to carbon nanotube (6, 0) as electrode of metal‐ion batteries: A theoretical study

“…[31][32][33][34][35] In this study, in order to estimate the real environment the effects of water (dielectric constant is 78.54) as polar solvent on V cell are calculated by conductor-like screening model (COSMO). [36][37][38][39][40][41][42] The free Gibbs energy (G) values of CNT and their complexes with metal oxides are calculated by using of geometry optimization and computation of harmonic vibrational frequencies at room temperature…”

A 5 V-class cobalt-free battery cathode with high loading enabled by dry coating

“…In these cases, the works targeting practical loadings were limited by either a low cycle number (less than 300 cycles) or poor capacity utilization. [21][22][23] To realize the full potential of LNMO, high loading must be achieved simultaneously with other modifications. Many fabrication strategies have been explored, including repeated coextrusion/assembly to create artificial channels to reduce tortuosity and improve the ionic flow, 24 dispersing singlewalled carbon nanotubes (SWCNTs) to fabricate 800 mm electrodes, 25 utilizing novel binders such as polyacrylonitrile (PAN) to enable high loading, 21 and adjusting the solid content in water based slurry with carbon micro fibers (CMFs).…”

“…In these cases, the works targeting practical loadings were limited by either a low cycle number (less than 300 cycles) or poor capacity utilization. 21–23…”