LiNi0.5Mn1.5O4 Addition to Anion-Storing Graphite Cathode Yields Multifaceted Benefits to Dual Graphite Batteries

Abstract

Abstract Dual graphite batteries (DGBs) yield an output voltage of ~ 4.5 V vs. Li+/Li by functioning on the ‘scissor-cutting’ type dual-ion storing mechanism. However, they lack capacity, suffer from poor cycling efficiency, and exhibit insufficient cycle life. The improvement strategies reported in the literature ameliorate only the targeted parameter but downgrade the rest. Herein, the approach of blending LiNi0.5Mn1.5O4 (LNMO) spinel oxide with graphite at cathode is demonstrated as a multifunctional remedy. LNMO represents an additional lithium reservoir that replenishes the depleted lithium at anode during cycling, thereby boosting cycling efficiency. It acts as a sacrificial salt that compensates the irreversibly consumed Li+ from its stock during parasitic reactions, thus reducing the self-discharge rate of dual-graphite full cell. Further, the Ni4+/2+ redox couple at ~ 4.75 V vs. Li+/Li in LNMO enhances capacity, upshifts average discharge voltage, and increases the energy output of the full cell. The interaction between de/intercalating Li+ and PF_6^- during the ‘cooperated scissor-cutting mechanism’ functional at blended cathode decreases charge transfer resistance. The presence of LNMO enriches the interfacial composition in inorganic components that benefits long-term cycling. Moreover, the physical properties like tap density, durability, and pore structure are reinforced in graphite/ LNMO blended cathode.