This review will delve into the inherent connections and distinctions of CO₂-directed conversion in ECO₂RR and CO₂ batteries, in terms of product types, catalyst selection, catalytic mechanisms, and electrochemical performances, while proposing a benchmarking framework for the evaluation of CO₂ batteries and innovative CO₂ battery configurations for practical applications.

ABSTRACT

Renewable electricity storage coupled with CO₂ conversion (power-to-X) has emerged as a fantastic means for reconciling energy demand and CO₂ mitigation issues. To successfully implement such approaches, directional CO₂ conversion is a crucial prerequisite, making it a pivotal research area. Thereinto, direct electrolysis of CO₂ (power-to-chemicals), while far from being commercially successful, has achieved substantial progress in selectivity and conversion rate for certain chemicals. Metal–CO₂ (M-CO₂) batteries can integrate several energy conversion pathways (power-to-metal paired with metal-to-power and/or metal-to-chemicals); however, their progress remains limited, particularly for directional generation of valuable chemicals. Meanwhile, the lack of understanding and benchmarking across materials and performances hinders rational evaluation and technology advancement of M-CO₂ batteries. Herein, we explore the critical elements required to achieve directional CO₂ conversion in M-CO₂ battery by comparing with direct electrocatalytic CO₂ reduction technology, building from fundamental chemistry concepts and issues, basis of materials design and product selectivity, to device-level considerations that facilitate high practical energy and power density, as well as long-duration conversion and storage. The emphasis lies on how to rationally design a precise catalyst and configuration for M-CO₂ batteries, with the expectation that forward-looking insights will inspire top-notch investigations and engage various sectors of society.