Decomposition of Li₂O₂ as the Cathode Prelithiation Additive for Lithium-Ion Batteries without an Additional Catalyst and the Initial Performance Investigation

Abstract

Compared to the graphite anode, Si and SiOx-containing anodes usually have a larger initial capacity loss (ICL) due to more parasitic reactions. The higher ICL of the anode can cause significant Li inventory loss in a full cell, leading to a compromised energy density. As one way to mitigate such Li inventory loss, Li2O2 can be used as the cathode prelithiation additive to provide additional lithium. However, an additional catalyst is usually needed to lower its decomposition potential. In this work, we investigate the use of Li2O2 as the cathode prelithiation additive without the addition of a catalyst. Li2O2 decomposition is first demonstrated in coin half-cells with a calculated capacity of 1180 mAh/g obtained from Li2O2 decomposition. We then further demonstrate successful Li2O2 decomposition in single-layer pouch (SLP) full cells and evaluate the initial electrochemical performance. Despite its moisture sensitivity, Li2O2 showed reasonable compatibility with dry-room handling. After dry-room handling, Li2O2 decomposition was observed with an onset potential of 4.29 V vs. SiOx anode in SLP cells. With Li2O2 addition, the utilization of the Li inventory from cathode active material was improved by 12.9%, and discharge DCR has reduced by 7% while the cells still deliver similar cell capacities.

Mo2C catalyzed low-voltage prelithiation using nano-Li2C2O4 for high-energy lithium-ion batteries

“…Surprisingly, self-sacrificial lithium salts usually have a high lithium-compensation capacity, and the gas products generated in the first charge can be effectively expelled from the battery. The reported sacrificial lithium salts include Li 3 N [10], Li 2 S [11], Li 2 O 2 [12], and Li 2 C 2 O 4 [13]. The air sensitivities of Li 3 N, Li 2 S, and Li 2 O 2 place stringent requirements on the operating environment [14].…”

Opportunities and Challenges of Li2C4O4 as Pre‐Lithiation Additive for the Positive Electrode in NMC622||Silicon/Graphite Lithium Ion Cells

“…Previous works have reported the need of reducing the particle size of pre‐lithiation cathode additives to promote complete decomposition at potentials <4.3 V (vs Li|Li + ) due to the low electronic conductivity of some additives (e.g., Li 2 O, [ 25 ] Li 2 O 2 , [ 18,26a ] and Na 2 C 4 O 4 [ 28a ] ). Particle size and morphology of pre‐lithiation additives are likely to impact the decomposition potential of the additive (i.e., lower decomposition potentials by decreasing the particle size) and the attainable charge capacity at a certain operating potential window (i.e., higher attainable capacity by decreasing the particle size).…”

“…[ 7b ] An ideal pre‐lithiation additive has to irreversibly release extra Li + in the working potential range of the cathode active material, exhibit a high volumetric and gravimetric capacity, does not result in strong dead weight residues after use, and be only electrochemically active in the first charge of a LIB cell to compensate for ALL due to SEI formation at the anode surface. [ 7a ] Several lithium compounds have been investigated as cathode additives so far, including binary compounds, such as Li 2 S, [ 14 ] Li 3 N, [ 15 ] LiN 3 , [ 16 ] Li 2 O, [ 17 ] Li 2 O 2 , [ 18 ] and LiF, [ 19 ] as well as ternary compounds, such as Li 5 FeO 4 , [ 20 ] Li 2 NiO 2 , [ 21 ] Li 6 CoO 4 , [ 22 ] and Li 2 MoO 3 . [ 23 ] However, most of these additives are unstable in ambient atmosphere or incompatible with standard cathode processing protocols, e.g., using N ‐methyl‐2‐pyrrolidone (NMP) as solvent.…”

High-Energy-Density and Long-Lifetime Lithium-Ion Battery Enabled by a Stabilized Li2O2 Cathode Prelithiation Additive

“…As illustrated in Figure , after PMMA dissolution, Li 2 O 2 in cathodes afforded additional Li ions to compensate for the active Li loss. In parallel, nanovoids formed as electrolyte reservoirs during the initial cell charge process, facilitating ion transport in cathodes. , …”

“…In parallel, nanovoids formed as electrolyte reservoirs during the initial cell charge process, facilitating ion transport in cathodes. 32,33 Diffraction and microscopic techniques were applied to characterize the structure and morphology of the assynthesized P-Li 2 O 2 samples. As shown by the X-ray diffraction (XRD) pattern (Figure 2a), P-Li 2 O 2 exhibits eight diffraction peaks at 23.2, 32.9, 35.0, 40.6, 47.5, 48.9, 59.0, and 70.2°, corresponding to the (002), (100), (101), (102), (004), (103), (104), and (201) planes of Li 2 O 2 , respectively (JCPDS no.…”