A Review: Pre‐lithiation Strategies Based on Cathode Sacrificial Lithium Salts for Lithium‐Ion Capacitors

Abstract

Similar to lithium‐ion batteries (LIBs), during the first charge/discharge process of lithium‐ion capacitors (LICs), lithium‐intercalated anodes (e.g., silicon, graphite, and hard carbon) also exhibit irreversible lithium intercalation behaviors, such as the formation of a solid electrolyte interface (SEI), which will consume Li+ in the electrolyte and significantly reduce the electrochemical performance of the system. Therefore, pre‐lithiation is an indispensable procedure for LICs. At present, commercial LICs mostly use lithium metal as the lithium source to compensate for the irreversible capacity loss, which has the demerits of operational complexity and danger. However, the pre‐lithiation strategy based on cathode sacrificial lithium salts (CSLSs) has been proposed, which has the advantages of low cost, simple operation, environmental protection, and safety. Therefore, there is an urgent need for a timely and comprehensive summary of the application of CSLSs to LICs. In this review, the important roles of pre‐lithiation in LICs are detailed, and different pre‐lithiation methods are reviewed and compared systematically and comprehensively. After that, we systematically discuss the pre‐lithiation strategies based on CSLSs and mainly introduce the lithium extraction mechanism of CSLSs and the influence of intrinsic characteristics and doping amount of CSLSs on LICs performance. In addition, a summary and outlook are conducted, aiming to provide the essential basic knowledge and guidance for developing a new pre‐lithiation technology.

PEDOT Nanowires Connecting Exfoliated HNb3O8 Nanosheets as High-Rate Anode for Lithium-Ion Capacitor

“…Meanwhile, YP-50F exhibits a stable cycling performance after 300 continuous cycles at 0.1 A g –1 (Figure S7f). It is worth noting that prelithiation of E-HNb 3 O 8 -PEDOT-0.2 electrode is required for assembling the LIC full cell. − This procedure was conducted by charging and discharging the E-HNb 3 O 8 -PEDOT-0.2 at 0.1 A g –1 for 10 cycles in the voltage range of 0.01–3.0 V and finally the E-HNb 3 O 8 -PEDOT-0.2 was lithiated at 0.01 V. Meanwhile, the mass ratios of cathode to the anode in the full cells are also optimized to gain a maximum energy output. As depicted in Figure S8, at an optimized mass ratio of 4:1, the full cell exhibits the largest discharging time, showing that the maximum specific capacity has been achieved at this mass ratio.…”

Pre‐Lithiation Technology for Rechargeable Lithium‐Ion Batteries: Principles, Applications, and Perspectives

“…Different from anode pre‐lithiation, cathode pre‐lithiation is indirectly pre‐lithiated by supplementing lithium into the LIBs system. The cathode pre‐lithiation methods in this section are divided into two main types, the first is using pre‐lithiation cathode additive and the other is the direct use of extra lithium ions to prepare the over‐lithiated cathode materials, both of them can compensate for the ICL during the initial charge process [104–107] …”

A perspective on the evolution and journey of different types of lithium-ion capacitors: mechanisms, energy-power balance, applicability, and commercialization

“…Thus, the development of LIC technology with optimum performance is highly dependent on precise and effective pre-lithiation. 56,[101][102][103][104][105][106][107][108] So, herein, we will discuss the role, mechanism changes, and common methods of pre-lithiation as follows.…”