Zhang Ruding, Huang Jiajia, Deng Wenzhuo, Bao Jingze, Pan Yilong, Huang Shuping, Sun Chuan-Fu
CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China.
College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350108, P. R. China.
Angew Chem Int Ed Engl. 2019 Nov 11;58(46):16474-16479. doi: 10.1002/anie.201909202. Epub 2019 Sep 25.
A key challenge for potassium-ion batteries is to explore low-cost electrode materials that allow fast and reversible insertion of large-ionic-size K . Here, we report an inorganic-open-framework anode (KTiOPO ), which achieves a reversible capacity of up to 102 mAh g (307 mAh cm ), flat voltage plateaus at a safe average potential of 0.82 V (vs. K/K ), a long lifespan of over 200 cycles, and K -transport kinetics ≈10 times faster than those of Na-superionic conductors. Combined experimental analysis and first-principles calculations reveal a charge storage mechanism involving biphasic and solid solution reactions and a cell volume change (9.5 %) even smaller than that for Li -insertion into graphite (≈10 %). KTiOPO exhibits quasi-3D lattice expansion on K intercalation, enabling the disintegration of small lattice strain and thus high structural stability. The inorganic open-frameworks may open a new avenue for exploring low-cost, stable and fast-kinetic battery chemistry.
钾离子电池面临的一个关键挑战是探索低成本的电极材料，以实现大离子尺寸的钾离子快速且可逆地嵌入。在此，我们报道了一种无机开放框架阳极（KTiOPO ），其可逆容量高达102 mAh g（307 mAh cm ），在0.82 V（相对于K/K ）的安全平均电位下具有平坦的电压平台，循环寿命超过200次，并且钾离子传输动力学比钠超离子导体快约10倍。结合实验分析和第一性原理计算揭示了一种涉及双相和固溶体反应的电荷存储机制，以及比锂嵌入石墨时（约10%）更小的电池体积变化（9.5%）。KTiOPO 在钾离子嵌入时表现出准三维晶格膨胀，能够消除小的晶格应变，从而具有高结构稳定性。无机开放框架可能为探索低成本、稳定且动力学快速的电池化学开辟一条新途径。
