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.

富含缺陷的异质界面与可调节的晶相和原子空位以及隐藏的介电响应特性相结合，有助于电磁耗散。然而，传统方法限制了它们精细的结构。在此，提出了一种创新的替代方案：卡拉胶辅助阳离子调节（CACR）策略，该策略诱导一系列硫化物纳米颗粒原位扎根于碳基质表面。这种独特的结构源于硫化物的战略空位形成能和强硫化物-碳支撑相互作用，有利于M _x S _y /碳复合材料（M-CA）中缺陷丰富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的偶极矩，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效应意为多功能性，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的 CA 相比，富含硫空位的异质结构 Co/Ni-CA 在仅 1.8 mm 处表现出 6.76 GHz 的宽吸收带宽。利用缺陷丰富的异质结构，这种一锅 CACR 策略可以指导先进纳米材料的设计和开发，增强电磁响应之外的跨不同应用领域的功能。