Fundamental Understanding of Nonaqueous and Hybrid Na–CO₂ Batteries: Challenges and Perspectives

Abstract

Alkali metal–CO2 batteries, which combine CO2 recycling with energy conversion and storage, are a promising way to address the energy crisis and global warming. Unfortunately, the limited cycle life, poor reversibility, and low energy efficiency of these batteries have hindered their commercialization. Li–CO2 battery systems have been intensively researched in these aspects over the past few years, however, the exploration of Na–CO2 batteries is still in its infancy. To improve the development of Na–CO2 batteries, one must have a full picture of the chemistry and electrochemistry controlling the operation of Na–CO2 batteries and a full understanding of the correlation between cell configurations and functionality therein. Here, recent advances in CO2 chemical and electrochemical mechanisms on nonaqueous Na–CO2 batteries and hybrid Na–CO2 batteries (including O2‐involved Na–O2/CO2 batteries) are reviewed in‐depth and comprehensively. Following this, the primary issues and challenges in various battery components are identified, and the design strategies for the interfacial structure of Na anodes, electrolyte properties, and cathode materials are explored, along with the correlations between cell configurations, functional materials, and comprehensive performances are established. Finally, the prospects and directions for rationally constructing Na–CO2 battery materials are foreseen.

CO2 Conversion Toward Real‐World Applications: Electrocatalysis versus CO2 Batteries

“…[ 23,24 ] Conversely, aqueous or hybrid metal‐CO 2 batteries can also store intermittent renewable electricity by using the metal as an energy storage carrier upon charging while supplying electricity and converting CO 2 to valuable carbon‐containing chemicals during discharging. [ 25,26 ] This discharge process is quite similar to ECO 2 RR which is driven by electrical input. But it can directly utilize the stored intermittent renewable electricity to convert CO 2 into chemical fuels and feedstocks, that is, energy conversion can be achieved in a single device that is obviously independent of the ECO 2 RR (Figure 1).…”

“…In the case of NASICON, for example, the ion transport is caused by the jumping of Na + ions between NASICON lattice gap positions, so that only Na + cations are allowed to be transported. [26] It physically separates the anode chamber from the aqueous cathode chamber, which effectively prevents the anode metal and organic electrolyte from being contaminated and ensures stable and safe operation of batteries. Liang et al [343,344] investigated the developing trend of the microstructure and macromorphology of NASICON in aqueous solutions with various pH values at ambient temperature (Figure 14f).…”

“…The decomposition of M 2 (CO 3 ) n during charging occurs at high potentials, which can lead to side effects such as the decomposition of electrolytes, giving rise to deteriorating cycling stability. [24,26] Therefore, outstanding bifunctional electrocatalysts are needed to provide active sites that contribute to CO 2 RR and CO 2 ER for reducing the overpotential during discharge and charging and thus improving the efficiency of energy conversion. Whereas in aqueous CO 2 batteries, the design of the electrocatalysis requires the ability to both promote highly active and selective CO 2 reduction with low overpotential and also to reduce the overpotential of the OER.…”

“…Regrettably, the research on M-CO 2 batteries, especially aqueous or hybrid M-CO 2 batteries is still in its infancy, despite the fact that they have the potential to realize dual functions of energy storage with high energy density and CO 2 conversion in a single device and are even anticipated to play a significant role in daily life, industrial production, and astronomical exploration. [25][26][27] A comprehensive and in-depth reference and suitable strategies can contribute to significant progress in CO 2 conversion and energy storage for this emerging energy technology.…”

Bimetallic-based composites for potassium-ion storage: challenges and perspectives

“…7,8 Supplement energy storage technologies based on other earth-abundant resources (Na, K, and Al) have emerged recently. [9][10][11][12][13] Thereinto, the standard electrode potential of K/K + (−2.93 V vs. SHE) is closer to that of Li/Li + (−3.04 V vs. SHE), 14,15 which is more negative in some electrolytes (e.g. PC and EC/DEC) and is one of the key factors to achieve high energy density.…”