The main bottleneck in the application of biomass-based carbon material in energy field is the development of an economical, nanoscale controllable and universal fabrication method. Herein, we demonstrate that a biomass-derived carbon consisting of loose carbon nanosphere clusters could serve as an ideal cathode material for high performance Li-O₂ batteries. The carbon nanomaterial can be prepared from both biomass derivatives and crude biomass by a low cost, facile and nanoscale controllable method. The open slit-shaped hierarchical pore structure endows the electrode sufficient active surface sites and mass transport channels that are not easily asphyxiated by the discharge products. The concentration of oxygenic groups and structure defects on the surface of obtained carbon materials is very low, which minimizes the side reactions associated with carbon decomposition. The unique pore structure and surface properties of the carbon electrode give rise to a superhigh specific capacity of 20300 mA h g^-1 and an extremely long cycle life which a cyclic capacity retention of 100% is maintained for 543 cycles with current density of 0.2 mA cm^-2 at controlled discharge-charge depths of 500 mA h g^-1.

生物质基碳材料在能源领域中应用的主要瓶颈是经济，纳米级可控且通用的制造方法的发展。本文中，我们证明了由松散的碳纳米球簇组成的生物质衍生碳可以用作高性能Li-O ₂的理想阴极材料电池。碳纳米材料可以通过低成本，简便且纳米级可控的方法由生物质衍生物和粗制生物质制备。开口的狭缝状分层孔结构赋予电极足够的活性表面位点和传质通道，这些通道不易被放电产物窒息。所获得的碳材料的表面上的氧基团和结构缺陷的浓度非常低，这使与碳分解有关的副反应最小化。碳电极的独特孔结构和表面特性可产生20300 mA hg ^-1的超高比容量，并具有极长的循环寿命，在电流密度为0.2 mA cm的情况下，在543个循环中可保持100％的循环容量^-2在受控的放电深度为500 mA hg ^-1时。