As a cathode material for potassium-ion batteries (PIBs), manganese-based layered oxides have attracted widespread attention due to their low cost, ease of synthesis, and high performance. However, the Jahn–Teller effect caused by Mn³⁺ and the irreversible phase transformation of the structure leads to poor cycle stability, limiting the development of layered oxides in PIBs. Herein, we demonstrate the use of phase-transition-free CaTiO₃ as rivets in K_0.5Mn_0.9Ti_0.1O₂ by a simple solid-state method. As verified by the in situ X-ray diffraction, the CaTiO₃ rivets effectively prevent the slippage of the transition metal layer during charge and discharge, inhibiting structural degradation. As a result, the obtained K_0.5Mn_0.9Ti_0.1O₂-0.02CaTiO₃ shows excellent cycling stability and rate performance, with high capacities of 119.3 and 70.1 mAh·g⁻¹ at 20 and 1000 mA·g⁻¹, respectively. At 200 mA·g⁻¹, the capacity retention remains 94.7% after more than 300 cycles. This work represents a new avenue for designing and optimizing layered cathode materials for PIBs and other batteries.

The urgent need for highly safe and sustainable large-scale energy storage systems for residential buildings has led to research into aqueous zinc ion batteries. However, when zinc is used in aqueous zinc ion batteries, it suffers from severe irreversibility due to its low Coulombic efficiency, dendrite growth, and side reactions. To address these challenges, we take advantage of organic cation to induce trifluoromethanesulfonate decomposition to build zinc fluoride/zinc sulfide-rich solid electrolyte interphase (SEI) that not only can adapt to a high areal capacity of deposition/stripping disturbance but also adjust zinc ion deposition path to eliminate dendrite. As a result, the unique interface can promote the Zn battery to achieve excellent electrochemical performance: high levels of plating/stripping Coulombic efficiency (99.8%), stability life (6,600 h), and cumulative capacity (66,000 mAh·cm⁻²) at 68% zinc utilization (20 mAh·cm⁻²). More importantly, the SEI significantly enhances the cyclability of full battery under limited Zn, lean electrolyte, and high areal capacity cathode conditions.

Low-cost preparation methods for cathodes with high capacity and long cycle life are crucial for commercializing potassium-ion batteries (PIBs). Presently, the charging/discharging strain that develops in the active cathode material of PIBs causes cracks in the particles, leading to a sharp capacity fade. Here, to abate the strain release and the need for an industrially relevant process, a simple low-cost co-precipitation method for synthesizing yolk–shell P3-type K_0.5[Mn_0.85Ni_0.1Co_0.05]O₂ (YS-KMNC) was reported. As cathode material for PIBs, the YS-KMNC delivers a high reversible capacity (96 mAh g^–1 at 20 mA g^–1) and excellent cycle stability (80.5% retention over 400 cycles at a high current density of 200 mA g^–1). More importantly, a full battery assembled with the YS-KMNC cathode and a commercial graphite anode exhibits a high operating voltage (0.5-3.4 V) and an excellent cycling performance (84.2% retention for 100 cycles at 100 mA g^–1). Considering the low-cost, simple production process and high performance of YS-KMNC cathode, this work could pave the way for the commercial development of PIBs.

Large-scale and low-cost preparation of carbon-based potassium anode with long life and high capacity is one of the footstones for the development of potassium ion batteries (PIBs). Herein, a low-cost carbon-based material, cross-linked hollow graphitic carbon (HGC), is large scale synthesized to apply for PIBs anode. Its hollow structure can afford sufficient space to overcome the damage caused by the volume expansion of graphitic carbon (GC). While the cross-linked structure forms a compact interconnection network that allows electrons to rapid transfer between different GC frameworks. Electrochemical measurements demonstrated that the HGC anode exhibited low charge/discharge plateau (about 0.25 V and 0.1 V) and excellent specific capacity as high as 298 mA h g⁻¹ at the current density of 50 mA g⁻¹. And more important, after 200 cycles the capacity of HGC anode still shows 269 mA h g⁻¹ (the decay rate of per cycle is only 0.048%). Meanwhile, the use of commercial traditional electrolyte (KPF₆) and cheap raw materials that provide new hope for trying and realizing the large-scale production of PIBs based on carbon anode materials.