In Situ Mitigation of First-Cycle Anode Irreversibility in a New Spinel/FeSb Lithium-Ion Cell Enabled via a Microwave-Assisted Chemical Lithiation Process

Abstract

First-cycle irreversibility is a major problem that plagues many next-generation nanoscale anode materials which form solid-electrolyte interphase (SEI) layers. Without a method to compensate for this irreversible capacity loss, the full cells will face serious problems. The concept of a lithium reservoir in spinel cathodes was proposed in the early 90s to combat the irreversibility of graphite anodes, but chemical techniques to lithiate spinel have been complex or hazardous. We present in this study (i) a new facile microwave-assisted chemical lithiation technique for spinel oxide cathodes which is capable of inserting one extra lithium per formula unit using less expensive, readily available lithium hydroxide in polyol and (ii) two new advanced lithium-ion batteries combining a prelithiated 5 V spinel Li 1 + x Mn 1.5 Ni 0.5 O 4 or a 4 V spinel Li 1.05 + x Ni 0.05 Mn 1.9 O 4 cathode and a carbon-free FeSb-TiC alloy anode that has a high first-cycle irreversible capacity loss. We show that the extra chemically inserted lithium is necessary to achieve a complete utilization of the cathode capacity. The battery employing the 5 V spinel cathode exhibits good rate capability with an energy density of 260 Wh/kg based on total active mass.