Li₂O:Li–Mn–O Disordered Rock‐Salt Nanocomposites as Cathode Prelithiation Additives for High‐Energy Density Li‐Ion Batteries

Abstract

The irreversible loss of lithium from the cathode material during the first cycles of rechargeable Li‐ion batteries notably reduces the overall cell capacity. Here, a new family of sacrificial cathode additives based on Li2O:Li2/3Mn1/3O5/6 composites synthesized by mechanochemical alloying is reported. These nanocomposites display record (but irreversible) capacities within the Li–Mn–O systems studied, of up to 1157 mAh g−1, which represents an increase of over 300% of the originally reported capacity in Li2/3Mn1/3O5/6 disordered rock salts. Such a high irreversible capacity is achieved by the reaction between Li2O and Li2/3Mn1/3O5/6 during the first charge, where electrochemically active Li2O acts as a Li+ donor. A 13% increase of the LiFePO4 and LiCoO2 first charge gravimetric capacities is demonstrated by the addition of only 2 wt% of the nanosized composite in the cathode mixture. This result shows the great potential of these newly discovered sacrificial additives to counteract initial losses of Li+ ions and improve battery performance.

Reversible densification in nano-Li2MnO3 cation disordered rock-salt Li-ion battery cathodes

“…9). This observation is in agreement with the recently reported ability of nanostructured Li-Mn-O disordered rock-salts to catalyse the electrochemical activation of Li 2 O in Li 2 O:Li-Mn-O nanocomposites 56 with superior rst charge capacities (>1100 mA h g À1 ) following the reactions:…”

Li trapping in nanolayers of cation ‘disordered’ rock-salt cathodes

“…Figure 5 summarises the theoretical, 1 st charge capacity and capacify fade rate of cathode materials cycled in half cells at room temperature. We compare the reported performance of cathode materials with no extra capacities (LiFePO4, [18] LiCoO2, [18] NMC811 [19] and NMC311 [19] ) to DRS cathodes with different extents of oxygen participation ranging from 25 to 100 % of the extra capacities beyond the theoretical value given by the transition metal redox limit. As shown in Figure 5, the higher 1 st charge capacities of DRS are accompanied by a higher rate of capacity fade.…”

“…While the capacity fade of cathode materials with no oxygen redox typically ranges from 0.2 up to 0.5%, the typical value of DRS is around one order of magnitude higher. [5][6][7]18,19] and the theoretical capacities were calculated using the transition metal redox activity.…”

Layered Oxide Cathode for Potassium‐Ion Battery: Recent Progress and Prospective

“…The bigger in M, the larger distance in the a lattice parameter; thereby, introduction of large cations, such as Sc 3+ and Y 3+ , could help to stabilize a O3‐type framework. In addition, similar to Li and Na systems, the issue is expected to be solved by potassium compensation through a pre‐potassiation process with metallic potassium [ 91 ] or incorporation of sacrificial cathode additives such as nitrides [ 92,93 ] and oxides, [ 94 ] which could also offset the initial potassium loss related to SEI films formed on anode materials.…”