Reserved Lithium-Ion Batteries for in Situ Lithiation of Vanadium Pentoxide Cathode

Abstract

The race to substitute gasoline-powered vehicles with electric ones has resulted in the boom of electric vehicles’ sales by about 20 times since 2011 till the present. This has triggered a huge supply-demand scenario for lithium-ion batteries (LIBs) around the globe. Currently, LIBs rely heavily on cathodes such as LiNixMnyCozO2, LiFePO4, LiNiO2, LiCoO2, to maintain their place to meet energy expectations. Rarely, lithium-free compounds have been used as positive electrodes due to the irreversibility of redox reactions and the requirement of lithium metal anode. These have restricted the further development of new cathode materials for lithium-ion batteries. Some of the materials are Cr3O4, ZnO, TiO2, MnO2, and V2O5. These materials have high theoretical capacities, however, except V2O5, other materials have a low potential for insertion/extraction of Li+ ions and can possibly be reduced to the metal state during intercalation reactions. To ensure practicality and feasibility of such materials, it is important to focus on the lithiation strategies, viz., lithium additives, pre-lithiation of the anode,film-forming additives, and blended cathodes. However, these approaches cause cell voltage modification due to the presence of Li+ ion voids in the electrode. Fortunately, the pre-lithiation of the anode compensates for the initial loss of lithium ions in the formation of the solid electrolyte interface (SEI). However, the pre-lithiation technique is complex and uneconomical, resulting in it being infeasible in the commercial applications.Here we report, in situ lithiation of the electrodes for the advancement of the lithium-free cathode research using lithium-electrode as a reservoir. The presence of a third reservoir electrode in LIB is brought only into the cell circuit initially during the SEI formation process and lithiation of the electrode. Here, V2O5 cathode with meso carbon microbeads (MCMB) was used to fabricate high specific capacity and high energy-density reserved lithium-ion batteries (RLIBs). The RLIB system delivered a high charge specific capacity of 245 mAh g-1 following two Li+ ions insertion/extraction. The tri-electrode system provided an initial high energy density of 980 Wh kg-1. A comparison of performance between V2O5 half-cell, V2O5-MCMB full-cell, and RLIB was made. There is a stark resemblance in the performance of RLIB performance with half-cell profile and in terms of capacity versus cycle number. Multiple module calorimetry provided the thermal heat signature to elucidate the safety features of the proposed RLIB system and compare it to the existing LIBs. Using this innovative concept of reservoir charging would be of key importance and valuable for applications in various sectors of society. Figure 1