Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies, as well as veiled dielectric-responsive character, are instrumental in electromagnetic dissipation. Conventional methods, however, constrain their delicate constructions. Herein, an innovative alternative is proposed: carrageenan-assistant cations-regulated (CACR) strategy, which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix. This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction, benefiting the delicate construction of defects-rich heterostructures in M_xS_y/carbon composites (M-CAs). Impressively, these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and, simultaneously, induct local asymmetry of electronic structure to evoke large dipole moment, ultimately leading to polarization coupling, i.e., defect-type interfacial polarization. Such “Janus effect” (Janus effect means versatility, as in the Greek two-headed Janus) of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time. Consequently, the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm, compared to sulfur vacancies-free CAs without any dielectric response. Harnessing defects-rich heterostructures, this one-pot CACR strategy may steer the design and development of advanced nanomaterials, boosting functionality across diverse application domains beyond electromagnetic response.

与可调节晶相和原子空位以及隐蔽的介电响应特性集成的富含缺陷的异质界面有助于电磁耗散。然而，传统方法限制了它们的精致结构。在此，提出了一种创新的替代方案：角叉菜胶辅助阳离子调节 （CACR） 策略，该策略诱导一系列原位扎根于碳基质表面的硫化物纳米颗粒。这种独特的构型源于硫化物的战略空位形成能和强硫化物-碳载体相互作用，有利于 M _x S _y /碳复合材料 （M-CAs） 中富含缺陷的异质结构的精细构建。令人印象深刻的是，这些产生的硫空位首先被发现增强了异质界面处的电子积累/消耗能力，同时诱导电子结构的局部不对称性以引起大偶极矩，最终导致极化耦合，即缺陷型界面极化。这种界面硫空位的“Janus 效应”（Janus 效应意味着多功能性，如希腊语中的双头 Janus）首次被理论和实验研究直观地证实。因此，与没有任何介电响应的无硫空位 CA 相比，富含硫空位的异质结构 Co/Ni-CA 在仅 1.8 mm 处显示出 6.76 GHz 的宽吸收带宽。利用富含缺陷的异质结构，这种一锅法 CACR 策略可以指导先进纳米材料的设计和开发，从而增强电磁响应以外的不同应用领域的功能。