Unveiling two-dimensional TiS₂ as an insertion host for the construction of high energy Li-ion capacitors

Herein, we report, for the first time, the possibility of using TiS₂ as an insertion host for the fabrication of high energy and high power Li-ion capacitors with commercial activated carbon (AC). The Li-insertion and PF₆^- adsorption/desorption properties are determined using Li in TiS₂ and AC electrodes, respectively, which is very useful to balance the mass loading between the electrodes to realize maximum energy. Under balanced loading, the AC/TiS₂ based LIC delivers a maximum energy density of ∼49 W h kg^-1. Upon long-term cycling, the AC/TiS₂ based LIC experiences a marginal fade in density; specifically ∼76% of its initial value is retained after 2000 cycles. Prior to this, a nearly 100% crystalline TiS₂ insertion host was prepared via chemical vapor transport with high yield.