High‐performance Li‐ion Battery based on Cr‐Substituted Lithium Manganite and Lithium Titanate Spinels: Influence of Mass Balance on its Electrochemistry

Abstract

AbstractThe influence of mass balance in the LiCr0.2Ni0.4Mn1.4O4//Li4Ti5O12 (LCrNMO//LTO) full cell on its electrochemical performance at different rates is described. The effect of the variation of the molar fraction of LTO to LCrNMO (χ) at different rates is described in detail. The full cell showed a reversible working potential at about 3 V. For every rate tested, the discharge capacity, normalized to total mass of both electrode materials (Qdch), reached a maximum value approximately at the stoichiometric value of χ=1. When χ<1, Qdch is limited by an incomplete electrochemical reaction of the LCrNMO cathode and when χ>1 Qdch decreases due to the increase in the total weight of active electrode materials. When the discharge rates were increased to ≥1 C (1 C=147.5 mA g−1 or 0.260 mA cm−2), the maximum Qdch delivered by the full cell was shifted slightly beyond the stoichiometry (χ=1.1). Furthermore, the LCrNMO//LTO full cell exhibited an outstanding ultralong cycling behavior: with a capacity retention of 93 % after 1000 cycles. Its cyclability is as high as 99.994 %. The LiCrNMO//LTO full cell is a promising lithium‐ion battery for practical applications, especially for plug‐in hybrid electric vehicles, for which a long cycle life and reasonable power are required. However, it is demonstrated that the optimization of anode to cathode materials is one of the most important parameters to take into account to achieve high energy and power densities.