Realizing 200mAh g-1 Lithium Manganese Oxide Spinel in Lithium Ion Battery with Prelithiated Anode

At present, the global market size of Li ion battery is dramatically increasing as its application in large scale system such as electric vehicle (EV) and energy storage system (ESS) expands intensely. Accordingly, the development of high-energy-density battery for their application is urgently needed. Today, energy density of Li ion battery largely depends on the specific capacity of cathode active material. The specific practical capacity of conventional cathode active materials such as LMO (Lithium Manganese Oxide Spinel, 4V region), LNMC (Lithium Nickel Manganese Cobalt Layered Oxide), and LFP (Lithium Iron Phosphate Olivine) is 100-170 mAh/g and the utilization of cathode active materials of even higher specific capacity is essential for the development of high-energy-density battery. Cathode active materials such as sulfur, oxygen, LMO (3+4V region) have theoretically very high specific capacity (270 – 3800 mAh/g), however, cannot be adopted in today’s Li ion battery industry because in their structure they do not possess lithium which is vital for electrochemical reaction in Li ion battery. To utilize these non-lithiated cathode active materials, additional lithium must be provided to the cell. Li half-cell where Li-foil is used as the anode in the cell could be a candidate, however, the Li dendrite growth problem which might lead to battery explosion should be precedently solved for practical application. More desirable and rather easily applicable solution is the prelithiation strategy in which anode or cathode is chemically lithiated (via lithium intercalation or alloying) by short-circuit reaction between the electrode and lithium source such as lithium foil, gas or powder. The prelithiation of anode is preferred because the cathode prelithiation might yield safety problem with excessive generation of heat of reaction. In this study, we propose an elegant prelithiation mechanism in graphite anode based on the results of electrochemical reaction and physico-chemical analyses. We demonstrate the prelithiation methodology that is directly applicable in practice with high prelithiation yield (efficiency) by controlling the relevant important variables. We also show that the developed prelithiation methodology can be applied for designing and operating full cell battery in which non- (or partially) lithiated LMO is adopted as cathode active material, which delivers ~200 mAh/g in 3+4V region with good cycle capability.