B/N/O-Codoped 2D Porous Carbon Nanosheets for High-Performance Dual-Carbon Lithium-Ion Capacitors

Abstract

The development of dual-carbon lithium-ion capacitors (DC-LICs) with high energy at high power density is still a challenge due to the mismatch of capacity and dynamics of battery-type anodes/capacitor-type cathodes. Two-dimensional porous carbon nanosheets (2D-PCS) possess a large open flat layer with nanoscale thickness, exposing more active sites and shortening the ion diffusion route, which can effectively resolve the mismatch issue in DC-LICs. However, developing an easy-to-manipulate and widely available method to prepare 2D-PCS is still a challenge. Herein, using borax as the poreforming agent and heteroatom dopants, an electrode with a 2D-PCS structure is obtained (noted as C-B-2). Benefiting from the open structure and doping effect, C-B-2 shows a satisfactory rate ability and high capacity both as a cathode and an anode. Besides, a symmetric "dual-carbon" device C-B-2//C-B-2 LIC working in the 0.01−4.5 V range was successfully fabricated, demonstrating a high energy density of 173.1 Wh kg −1 at a power density of 225.5 W kg −1 and a superior cycling stability of 10,000 cycles at 2 A g −1 . Furthermore, the C-B-2//C-B-2 LICs demonstrate their practical application potential in successfully powering color LEDs. This work provides an efficient method for developing highly efficient DC-LIC devices.

Recent Advances in Hybrid Lithium-Ion Capacitors: Materials and Processes

“…As a key component of LICs supporting the high-rate charging–discharging and high power density, the cathode materials require some specific attributes, including high electronic conductivity, a substantial specific surface area (exceeding 1000 m 2 g –1 ), well-developed pore structure, high volumetric density, and commendable electrochemical inertness. The most commonly used cathode materials for LICs are capacitive carbonaceous materials, − including activated carbon (AC), templated mesoporous carbon, carbon nanotubes (CNTs), graphene (G), and carbon aerogels, etc. ,− The cost-effectiveness and availability from renewable resources further enhance their commercial value. Among these materials, AC stands out as the preferred and widely utilized cathode material for LICs, making it the most widely used and commercially available option .…”

Temperature-Regulated Prelithiated Graphite Anode for an Improved Lithium-Ion Capacitor

“…The direct-contact prelithiation (DC-Pr) method, which utilizes the potential difference between the anode and the metallic lithium to induce electron migration and guide lithium ions through the electrolyte to insert from metallic lithium into the anode, can efficiently achieve a stable solid–electrolyte interface (SEI) on the anode, similar to that obtained through other prelithiation methods. , Moreover, the DC-Pr method not only simplifies the complex electrode assembly and disassembly process but also allows for control over the degree of prelithiation by adjusting the contact time. , Therefore, the DC-Pr method represents a simple, practical, and scalable approach that is widely compatible with electrode manufacturing processes; it can be easily implemented across various sizes and types of electrode fabrication, offering an effective means to enhance the LIC performance.…”