High-voltage lithium metal batteries (LMBs) utilizing lithium-rich manganese oxide (LRMO) cathodes offer a promising way towards high energy densities yet remain impractical when operating at high voltages, primarily due to electrolyte instability at interfaces of LRMO and Li metal electrodes. In this study, we report stable cycling of LRMO-based LMBs under ultra-high voltage conditions of 5 V via employing an aggregation-enhanced solvation electrolyte (AESE). The AESE features a solvation structure dominated by anion-wrapped aggregates, in which Li⁺ ions are under a coordination environment surrounded by numerous anions. With such a solvation structure, the AESE concurrently stabilizes the Li metal anode and LRMO cathode. It promotes a protective cathode–electrolyte interphase on LRMO and an inorganic-rich interphase on Li metal, collectively suppressing electrolyte oxidation and transition metal dissolution. Thereby, Li||LRMO cells can deliver exceptional cycling stability at 5 V, retaining >87% capacity after 200 cycles. It also sustains stable operation for 100 cycles at −20 °C. This work demonstrates the electrolyte design for 5 V-class LMBs capable of reliable operation under low-temperature conditions.

Enhancing the cut-off voltage of high-nickel layered oxide cathodes is an efficient way to obtain higher energy density of lithium-metal batteries (LMBs). However, the phase transition of the cathode materials and the uncontrolled decomposition of the electrolytes at high voltage can lead to irreversible dissolution of transition metal ions, which might cause the crossover effects on the lithium metal anodes. Nonetheless, the mechanism and electrolyte dependence of the crossover effects for Li metal anodes are still unclear. Herein, we investigate the crossover effects between LiNi_0.8Mn_0.1Co_0.1O₂ and Li-metal anode in two electrolyte systems. For ether-based electrolyte, its poor oxidation stability results in massive dissolution of transition metal ions, leading to dendrite growth on anode and rapid cells failure. Conversely, ester-based electrolyte exhibits good electrochemical performances at 4.5 V with little crossover effect. This study provides an idea for electrolyte systems selection for high-voltage LMBs, and verifies that the crossover effect should not be neglected in LMBs.

Porous carbon materials play essential roles in electrocatalysis and electrochemical energy storage. It is of significant importance to rationally design and tune their porous structure and active sites for achieving high electrochemical activity and stability. Herein, we develop a novel approach to tune the morphology of porous carbon materials (PCM) by embedding fullerene C₆₀, achieving improved performance of oxygen reduction reaction (ORR) and lithium-sulfur (Li-S) battery. Owing to the strong interaction between C₆₀ and imidazole moieties, pomegranate-like hybrid of C₆₀-embedded zeolitic imidazolate framework (ZIF-67) precursor is synthesized, which is further pyrolyzed to form C₆₀-embedded cobalt/nitrogen-codoped porous carbon materials (abbreviated as C₆₀@Co-N-PCM). Remarkably, the unique structure of C₆₀@Co-N-PCM offers excellent ORR electrocatalytic activity and stability in alkaline solutions, outperforming the commercial Pt/C (20 wt.%) catalyst. Besides, C₆₀@Co-N-PCM as a novel cathode delivers a high specific capacity of ~ 900 mAh·g^-1 at 0.2 C rate in Li-S batteries, which is superior to the pristine ZIF-67-derived PCM without embedding C₆₀.