Sea urchin-inspired VS4 morphology for superior electrochemical performance in high-energy batteries

Electronically and ionically conductive sulfur-based cathode materials play a pivotal role in improving the electrochemical capabilities of high-energy rechargeable batteries. Among these, vanadium tetrasulfide (VS4) stands out for its remarkable specific capacity and cost-effectiveness, marking it as a notable contender. However, its intrinsic low conductivity and significant volume expansion during cycling pose challenges for its adoption in rechargeable batteries. Here, we introduce a "sea urchin"-like VS4 cathode material, characterized by a microsized core coupled with nanosized spines. This distinctive architecture is used to exploit the benefits of both micro- and nanosized electrode materials. The nano-sized spines, abundant in active sites, facilitate rapid electron and lithium-ion transport, thereby boosting catalytic activity. Moreover, the distinctive architecture offers ample space to accommodate volume expansion during cycling. The "sea urchin"-like VS4 cathode demonstrates a substantial specific capacity of approximately 994.1 mAh g-1 or 1671.7 Wh kg-1, maintaining a capacity of 670.0 mAh g-1 after 100 cycles at a 0.5 C rate. Furthermore, the unique morphology of the VS4 cathode ensures structural stability and minimal volume change during use, owing to the sufficient internal space. Our study facilitates potential of morphological innovations to enhance the electrochemical performance of electrode materials.