Hard carbon (HC) is an attractive anode material for low-cost and high-energy density sodium-ion batteries (SIBs); however, its low initial Coulombic efficiency (ICE) limits its practical battery application. To overcome this problem, we reported a facile strategy to compensate the irreversible capacity loss of HC anodes simply by a chemical presodiation reaction of the HC electrode with a sodiation reagent (sodium biphenyl, Na-Bp). Benefiting from the strong sodiation ability of Na-Bp, HC anodes can be presodiated rapidly in a very short time and the presodiated HC (Na_xHC) is found to have a desirable ICE of 100%. When coupled with the Na₃V₂(PO₄)₃ cathode to build a SIB full cell, the Na_xHC||Na₃V₂(PO₄)₃ cell exhibits a high ICE of ∼95.0% and an elevated energy density of 218 W h kg^–1, which are far superior to those of the control cell using a pristine HC anode (50% ICE and 120 W h kg^–1, respectively), suggesting great advantages brought about by the chemical presodiation process. More importantly, this presodiation reaction is very mild and highly efficient and can be widely extended to a variety of Na-storage materials, offering a new route to develop high-performance Na-storage materials for practical battery applications.

中文翻译：

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具有化学修饰的硬碳阳极，具有增强的初始库仑效率，可用于高能钠离子电池

硬碳（HC）是用于低成本和高能量密度钠离子电池（SIB）的有吸引力的阳极材料；但是，其较低的初始库仑效率（ICE）限制了其实际的电池应用。为了克服这个问题，我们报道了一种简便的策略，可以通过简单地通过HC电极与增碱剂（联苯钠，Na-Bp）的化学预沉淀反应来补偿HC阳极的不可逆容量损失。得益于Na-Bp的强大的制糖能力，HC阳极可以在很短的时间内迅速沉积，发现HC（Na _x HC）的ICE理想值为100％。当与Na ₃ V ₂（PO ₄）₃阴极耦合以构建SIB全电池时，Na _xHC || Na ₃ V ₂（PO ₄）₃电池具有约95.0％的高ICE和218 W h kg ^–1的高能量密度，远优于使用原始HC阳极的对照电池（ 50％的ICE和120 W h kg ^–1），表明化学沉淀法带来了巨大的优势。更重要的是，这种预沉淀反应非常温和高效，可以广泛地扩展到各种Na存储材料，为开发用于实际电池应用的高性能Na存储材料提供了一条新途径。