Potassium-ion batteries (PIBs) have the potential to be used in future large-scale energy storage devices because of the abundance of potassium resources and their relatively high energy density. However, low reversible capacity and poor cycling stability caused by the large size of the potassium ions limit their practical application. N-doped bacterial cellulose-derived carbons (NBCCs) were prepared by impregnating bacterial cellulose with Mg(NO₃)₂ solutions (0.03, 0.05 and 0.07 mol L⁻¹) as a pore template and nitrogen source, followed by carbonization and acid washing. The effects of the Mg(NO₃)₂ concentration on the morphology, porosity, N doping level and electrochemical performance of the NBCCs were investigated. NBCC (0.05) is the best of the three because it has an interconnected pore network structure with a homogeneous distribution of N at a concentration of 3.38 at% and a high specific surface area of 1355 m² g⁻¹. It delivers an excellent rate capability of 134 mAh g⁻¹ at 5 A g⁻¹ and a capacity of 307 mAh g⁻¹ after 2500 cycles at 2 A g⁻¹. A NBCC (0.05)-based anode in a potassium ion hybrid capacitor has a high energy density of 166 W h kg⁻¹ at a power density 493 W kg⁻¹ and excellent cyclability with a capacityretention of nearly 95% after 2000 cycles. This simple synthesis strategy for fabricating carbon anode materials with an excellent electrochemical performance should promote the development of green and large-scale energy storage devices.

由于钾资源丰富且能量密度较高，钾离子电池（PIB）可能会在未来的大型储能设备中使用。然而，由于钾离子的大尺寸引起的低可逆容量和差的循环稳定性限制了它们的实际应用。通过将Mg（NO ₃）₂溶液（0.03、0.05和0.07 mol L ^-1）作为孔模板和氮源浸渍细菌纤维素，然后进行碳化和酸洗，来制备N掺杂细菌纤维素衍生的碳（NBCC）。。Mg（NO ₃）_2的作用研究了浓度对NBCCs的形貌，孔隙率，N掺杂水平和电化学性能的影响。NBCC（0.05）是三者中最好的，因为它具有相互连接的孔网络结构，其中N浓度为3.38 at％且N比分布均匀，具有1355 m ² g ^-1的高比表面积。它在5 A g ^-1时具有134 mAh g ^-1的极佳速率能力，在2 A g ^-1 2500次循环后可提供307 mAh g ^-1的极佳速率。钾离子混合电容器中基于NBCC（0.05）的阳极在功率密度493 W kg ^-1时具有166 W h kg ^-1的高能量密度出色的可循环性，在2000次循环后的容量保持率接近95％。这种用于制造具有优异电化学性能的碳阳极材料的简单合成策略应促进绿色和大规模储能装置的发展。