High-Performance Dual-Ion Battery Based on Silicon–Graphene Composite Anode and Expanded Graphite Cathode

Abstract

Dual-ion batteries (DIBs) are a new kind of energy storage device that store energy involving the intercalation of both anions and cations on the cathode and anode simultaneously. They feature high output voltage, low cost, and good safety. Graphite was usually used as the cathode electrode because it could accommodate the intercalation of anions (i.e., PF6−, BF4−, ClO4−) at high cut-off voltages (up to 5.2 V vs. Li+/Li). The alloying-type anode of Si can react with cations and boost an extreme theoretic storage capacity of 4200 mAh g−1. Therefore, it is an efficient method to improve the energy density of DIBs by combining graphite cathodes with high-capacity silicon anodes. However, the huge volume expansion and poor electrical conductivity of Si hinders its practical application. Up to now, there have been only a few reports about exploring Si as an anode in DIBs. Herein, we prepared a strongly coupled silicon and graphene composite (Si@G) anode through in-situ electrostatic self-assembly and a post-annealing reduction process and investigated it as an anode in full DIBs together with home-made expanded graphite (EG) as a fast kinetic cathode. Half-cell tests showed that the as-prepared Si@G anode could retain a maximum specific capacity of 1182.4 mAh g−1 after 100 cycles, whereas the bare Si anode only maintained 435.8 mAh g−1. Moreover, the full Si@G//EG DIBs achieved a high energy density of 367.84 Wh kg−1 at a power density of 855.43 W kg−1. The impressed electrochemical performances could be ascribed to the controlled volume expansion and improved conductivity as well as matched kinetics between the anode and cathode. Thus, this work offers a promising exploration for high energy DIBs.

Realized Record Capacity and Rate Performance of Dual-Carbon Batteries Constructed by Introducing Superhard Nanodiamonds

“…Performed at a high working potential voltage near 5.0 V, the redox reactions of anion intercalation/deintercalation in the traditional cathodes (e.g., graphite) of DIBs would normally lead to severe side reactions, such as irreversible decomposition of electrolytes, exfoliation of electrodes, and low Coulombic efficiency (CE) during the long-term cycling processes, which could directly reduce the service life of batteries. − All configurations of DIBs must be fully optimized to overcome these challenges. Up to now, extensive research related to exploring new materials, structural design, and modification techniques has been conducted, especially on anodes for effective Li-ion intercalation and deintercalation in DIBs. − However, the sluggish reaction kinetics and rate performances still need to be improved to match well with the cathode side. Advanced strategies of nanocrystallization, composite design, and alloy/intermetallic construction, etc.…”