Potassium ion batteries (KIBs) have emerged as a promising energy storage system, but the stability and high rate capability of their electrode materials, particularly carbon as the most investigated anode ones, become a primary challenge. Here, it is identified that pitch‐derived soft carbon, a nongraphitic carbonaceous species which is paid less attention in the battery field, holds special advantage in KIB anodes. The structural flexibility of soft carbon makes it convenient to tune its crystallization degree, thereby modulating the storage behavior of large‐sized K+ in the turbostratic carbon lattices to satisfy the need in structural resilience, low‐voltage feature, and high transportation kinetics. It is confirmed that a simple thermal control can produce structurally optimized soft carbon that has much better battery performance than its widely reported carbon counterparts such as graphite and hard carbon. The findings highlight the potential of soft carbon as an interesting category suitable for high‐performance KIB electrode and provide insights for understanding the complicated K+ storage mechanisms in KIBs.

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A crucial challenge for the commercialization of Ni-rich layered cathodes (LiNi0.88Co0.09Al0.03O2) is capacity decay during the cycling process, which originates from their interfacial instability and structural degradation. Herein, a one-step, dual-modified strategy is put forward to in situ synthesize the yttrium (Y)-doped and yttrium orthophosphate (YPO4)-modified LiNi0.88Co0.09Al0.03O2 cathode material. It is confirmed that the YPO4 coating layer as a good ion conductor can stabilize the solid–electrolyte interface, while the formative strong Y–O bond can bridle TM–O slabs to intensify the lattice structure in the state of deep delithium (>4.3 V). In particular, both the combined advantages effectively withstand the anisotropic strain generated upon the H2–H3 phase transition and further alleviate the crack generation in unit-cell dimensions, assuring a high-capacity delivery and fast Li+ diffusion kinetics. This dual-modified cathode shows advanced cycling stability (94.1% at 1C after 100 cycles in 2.7–4.3 V), even at a high cutoff voltage and high rate, and advanced rate capability (159.7 mAh g–1 at 10C). Therefore, it provides a novel solution to achieve both high capacity and highly stable cyclability in Ni-rich cathode materials.

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