Engineering multifunctional conductive carbon-based cathode additives to stabilize high-performance all-solid-state lithium metal batteries

Exceptional electrochemical performances of all-solid-state lithium metal batteries (ASSLMBs) can be achieved by effectively inhibiting damaging of reactive oxygen species (ROSs) formed by oxidation of the inevitably present surface groups on the carbon-based conductive agents (CCAs) and upon charging transition metal oxide based cathodes. Herein, we report on the use of highly effective novel CCA additive based on biomass-derived carbonaceous nanomaterials produced from carbonized pollen uniformly coated by nano MoO₂ through a bio-templating method (CP@MoO₂) in composite high energy cathodes of ASSLMBs. The rational design of this porous nano-composite additive not only makes it difficult for oxygen-containing functional groups to survive on the surface, but also promotes electrocatalytic adsorption and transformation of ROSs within composite cathodes, thus avoiding their detrimental effects. And rapid and homogeneous conductions of Li⁺/e⁻ within the composite cathodes are ensured thanks to the use of the CP@MoO₂ additive. As a result, ASSLMBs employing typical LiCoO₂ and promising Li-rich Mn-based oxide cathodes could demonstrate excellent cycling stability retaining 99.9 % of discharge capacity after 500 cycles at 0.2C and display capacity retention of over 87 % after 3000 cycles at 5C with a steady average coulombic efficiency (>99.98 %). © 2025 Elsevier Ltd