To ensure high capacity with reasonable cycling stability using the conversion or K-alloy reaction, the anode should minimize or embrace the volume expansion during the discharge (potassiation) and charge (depotassiation) processes. Herein, we report on a Bi₂Te₃ composite modified by nanosized carbon that boosts the highly reversible capacity with long cycling stability. The as-synthesized Bi₂Te₃ powders and acetylene black carbon were compositized via high-energy ball-milling, resulting in improvement of the electrical conductivity to ∼10⁻⁴ S cm⁻¹ from ∼10⁻⁷ S cm⁻¹. Electrochemical investigation revealed that the proposed Bi₂Te₃@C retained over 79.8% of its initial capacity (311 mAh g^− 1) for 500 cycles at a current of 1000 mA g^− 1. We unveil the reaction chemistry behind the acceptable performance using operando X-ray diffraction, X-ray absorption near edge structure spectroscopy, and time-of-flight secondary-ion mass spectrometry. The Bi₂Te₃ undergoes a conversion reaction to form Bi⁰ metal and K₂Te as a conversion byproduct, after which Bi is further potassiated to K₃Bi. The highly reversible behavior is attributed to the enlargement of the active area along with the filling of voids among Bi₂Te₃ particles by nanosized carbons in the composite electrode, enabling not only facile electron transport but also preservation of the electrode shape even after long-term cycling. Our approach highlights the feasibility of applying Bi₂Te₃@C as a sustainable anode material for potassium-ion batteries.

为了使用转化或钾合金反应确保高容量和合理的循环稳定性，阳极应最小化或包含放电（钾化）和充电（脱钾）过程中的体积膨胀。在此，我们报告了一种由纳米碳改性的 Bi ₂ Te ₃复合材料，该复合材料提高了具有长循环稳定性的高度可逆容量。所合成的Bi ₂特₃粉末和乙炔黑碳被compositized经由高能球磨，从而提高导电性的，以〜10 ^-4小号厘米^-1从〜10 ^-7小号厘米^-1. 电化学研究表明，所提出的 Bi ₂ Te ₃ @C在 1000 mA g ^{- 1}的电流下进行 500 次循环后仍能保持其初始容量（311 mAh g ^{-  1}）的79.8% 以上。我们使用原位X 射线衍射、X 射线吸收近边结构光谱和飞行时间二次离子质谱揭示了可接受性能背后的反应化学。Bi ₂ Te ₃经历转化反应以形成 Bi ⁰金属和 K ₂ Te 作为转化副产物，之后 Bi 进一步钾化为 K ₃ 双。这种高度可逆的行为归因于复合电极中纳米碳填充 Bi ₂ Te ₃颗粒之间的空隙扩大了活性面积，不仅使电子传输容易，而且即使在长时间使用后仍能保持电极形状。术语循环。我们的方法强调了应用 Bi ₂ Te ₃ @C 作为钾离子电池可持续负极材料的可行性。