Highly Rechargeable Lithium-CO2 Batteries with a Boron- and Nitrogen-Codoped Holey-Graphene Cathode

Light-Assisted Metal-Air Batteries: Progress, Challenges, and Perspectives

Metal-air batteries are considered one of the most promising next-generation energy storage devices owing to their ultrahigh theoretical specific energy. However, sluggish cathode kinetics (O₂ and CO₂ reduction/evolution) result in large overpotentials and low round-trip efficiencies which seriously hinder their practical applications. Utilizing light to drive slow cathode processes has increasingly becoming a promising solution to this issue. Considering the rapid development and emerging issues of this field, this Review summarizes the current understanding of light-assisted metal-air batteries in terms of configurations and mechanisms, provides general design strategies and specific examples of photocathodes, systematically discusses the influence of light on batteries, and finally identifies existing gaps and future priorities for the development of practical light-assisted metal-air batteries.

Cationic metal-organic framework derived ruthenium-copper nano-alloys in porous carbon to catalytically boost the cycle life of Li-CO2 batteries

Rechargeable Li-CO₂ batteries are an innovative energy storage technology with broad application prospects owing to their superb energy density and ability to capture the greenhouse gas CO₂. However, they are still suffering from severe challenges in the formation and decomposition of electrochemically sluggish Li₂CO₃ discharge products, resulting in poor battery performance. Development of an efficient cathodic electrocatalyst has the potential to address these issues by catalytically boosting the conversion of Li₂CO₃. Herein, we have designed a Ru-Cu nanoalloy decorated porous carbon (Ru-Cu@NPC) material derived from an anion-exchanged cationic MOF, and it can serve as an efficient cathode electrocatalyst for Li-CO₂ batteries. Benefitting from the uniform distribution of ultrafine Ru-Cu nanoalloys with high catalytic performance, Ru-Cu@NPC displays excellent CO₂ reduction and evolution activities. Impressively, the Li-CO₂ battery with the Ru-Cu@NPC catalyst exhibits a remarkably low potential gap of 0.93 V at 100 mA g^-1 and a stable discharge/charge cycling performance of more than 400 cycles at a high current density of 400 mA g^-1 within a limiting capacity of 1000 mA h g^-1. The study provides an opportunity for the research of cationic MOF derived bimetallic catalysts in the Li-CO₂ battery field.

Aprotic Lithium-Carbon Dioxide Batteries: Reaction Mechanism and Catalyst Design

In recent years, the combustion of fossil fuels leads to the release of a large amount of CO₂ gas, which induces the greenhouse effect and the energy crisis. To solve these problems, researchers have turned their focus to a novel Li-CO₂ battery (LCB). LCB has received much attention because of its high theoretical energy density and reversible CO₂ reduction/evolution process. So far, the emerging LCB still faces many challenges derived from the slow reaction kinetics of discharge products. In this review, the latest status and progress of LCB, especially the influence of the structure design of cathode catalysts on the battery performance, are systematically elaborated. This review summarizes in detail the existing issues and possible solutions of LCB, which is of high research value for further promoting the development of Li-Air battery.

High-Efficiency and Stable Li-CO2 Battery Enabled by Carbon Nanotube/Carbon Nitride Heterostructured Photocathode

Li-CO₂ batteries are explored as promising power systems to alleviate environmental issues and to implement space applications. However, sluggish cathode kinetics of CO₂ reduction/evolution result in low round-trip efficiency and poor cycling stability of the fabricated energy-storage devices. Herein, we design a heterostructued photocathode comprising carbon nanotube and carbon nitride to accelerate cathode reactions of a Li-CO₂ battery under illumination. Benefiting from the unique defective structure of carbon nitride and favorable interfacial charge transfer, the photocathode effectively harvests ultraviolet-visible light to generate abundant photoexcited carriers and coordinates energetic photoelectrons/holes to participate in the discharge/charge reactions, leading to efficient photo-energy utilization in decreasing reaction barriers and enhancing thermodynamic reversibility of Li-CO₂ battery. The resulting battery delivers a high round-trip efficiency of 98.8 % (ultralow voltage hysteresis of 0.04 V) and superior cycling stability (86.1 % efficiency retention after 100 cycles).

Interface Heteroatom-doping: Emerging Solutions to Silicon-based Anodes

Silicon-based composites have been recognized as a promising anode material for high-energy lithium-ion batteries (LIBs). However, the intrinsically low conductivity and the huge volume expansion during lithiation/delithiation progresses impede its further practical applications. In the past decades, numerous efforts have been made for surface and interface modification of Si-based anodes. Among these, doping of active materials with heteroatoms is one promising method to endow silicon many unmatched electrochemical properties. In this review, we focus on the effects of heteroatom doping on the interfacial properties of Si-based anodes, and some typical strategies for the interface doping are highlighted. We aim to give some reference for interfacial doping of Si-based anodes in LIBs.

High-Performance K-CO2 Batteries Based on Metal-Free Carbon Electrocatalysts

Metal-CO₂ batteries have attracted much attention owing to their high energy density and use of greenhouse CO₂ waste as the energy source. However, the increasing cost of lithium and the low discharge potential of Na-CO₂ batteries create obstacles for practical applications of Li/Na-CO₂ batteries. Recently, earth-abundant potassium ions have attracted considerable interest as fast ionic charge carriers for electrochemical energy storage. Herein, we report the first K-CO₂ battery with a carbon-based metal-free electrocatalyst. The battery shows a higher theoretical discharge potential (E^⊖ =2.48 V) than that of Na-CO₂ batteries (E^⊖ =2.35 V) and can operate for more than 250 cycles (1500 h) with a cutoff capacity of 300 mA h g^-1 . Combined DFT calculations and experimental observations revealed a reaction mechanism involving the reversible formation and decomposition of P12₁ /c1-type K₂ CO₃ at the efficient carbon-based catalyst.

Highly Efficient CO2 Utilization via Aqueous Zinc- or Aluminum-CO2 Systems for Hydrogen Gas Evolution and Electricity Production

Atmospheric carbon dioxide (CO₂ ) has increased from 278 to 408 parts per million (ppm) over the industrial period and has critically impacted climate change. In response to this crisis, carbon capture, utilization, and storage/sequestration technologies have been studied. So far, however, the economic feasibility of the existing conversion technologies is still inadequate owing to sluggish CO₂ conversion. Herein, we report an aqueous zinc- and aluminum-CO₂ system that utilizes acidity from spontaneous dissolution of CO₂ in aqueous solution to generate electrical energy and hydrogen (H₂ ). The system has a positively shifted onset potential of hydrogen evolution reaction (HER) by 0.4 V compared to a typical HER under alkaline conditions and facile HER kinetics with low Tafel slope of 34 mV dec^-1 . The Al-CO₂ system has a maximum power density of 125 mW cm^-2 which is the highest value among CO₂ utilization electrochemical system.