Dual-Carbon Lithium-Ion Capacitors: Principle, Materials, and Technologies

Lithium-ion capacitors (LICs) optimize energy density and power capability of lithium-ion batteries (LIBs) and electric double layer capacitors (EDLCs). The most promising LICs are those, called dual-carbon LICs, using the LIB carbonaceous negative electrode and EDLC activated carbon positive electrode due to the low lithiation-delithiation potential of carbonaceous materials and the excellent stability of activated carbon at high potentials. However, a pre-lithiation process is required to enable such LICs because both the carbonaceous materials used do not contain Li(+)ions. In this mini-review, the principle and materials of the dual-carbon LICs are outlined, and the key technologies are critically assessed.