Pre-lithiated Li4+xTi5O12 (0 ≤ x ≤ 3) anodes towards building high-performance Li-ion capacitors

Abstract

Spinel Li₄Ti₅O₁₂ is an extensively studied and successfully commercialized battery type electrode for lithium-ion capacitors (LICs), mainly due to its abundance, improved rate capability, and safety guaranteed by the high potential intercalation mechanism. However, still, there is an unanswered question – is prelithiation necessary for LTO-based LIC systems? In this work, we studied the role of prelithiation by assembling different LICs with LTO anodes by varying prelithiation levels (Li_4+xTi₅O₁₂, 0 ≤ x ≤ 3) with activated carbon (AC) electrodes. The disparities in electrochemical performance of such LICs, energy-power storage capability, and cycling stability are also investigated. The assembled AC/Li₄Ti₅O₁₂ cell shows a maximum energy storage capability of 84.59 W h kg⁻¹ at a current density of 0.05 A g⁻¹. And, a LIC with an optimum prelithiation level (∼30 min (50–55 mA h g⁻¹)) and AC/Li₅Ti₅O₁₂ configuration exhibits effective utilization of the voltage window. However, the process of prelithiation ensures the cycling stability of such LIC systems.