Phase change materials (PCMs) possess remarkable capability to store and release substantial amounts of energy during the processes of melting and crystallization across a wide temperature range, thus holding great promise in applications related to temperature regulation and thermal energy storage. Herein, to effectively address PCM leakage and enhance thermal conduction, PCM microcapsules with melamine–formaldehyde resin (MF) shell were prepared using in situ polymerization of Pickering emulsions stabilized by cellulose nanofibrils (CNFs). CNFs were selected as the stabilizers for the Pickering emulsions and as reinforcing nanofillers for the MF shell, owing to their excellent emulsifying capability, high mechanical strength, and sustainable nature. Paraffin wax (PW) was utilized as the PCM material. The resulting PCM microcapsules with MF resin shells and PW core had a diameter ranging from 2 to 4 µm. Results showed that microcapsule with the core–shell ratio of 2 (Micro-2.0) exhibited the highest latent heat of crystallization and latent heat of fusion, measuring approximately 128.40 J/g and 120.23 J/g, respectively. The encapsulation efficiency of Micro-2.0 was determined to be approximately 79.84%.

相变材料（PCM）具有在较宽温度范围内的熔化和结晶过程中存储和释放大量能量的卓越能力，因此在温度调节和热能存储相关的应用中具有广阔的前景。在此，为了有效解决PCM泄漏并增强导热性，利用纤维素纳米原纤维（CNF）稳定的Pickering乳液的原位聚合制备了具有三聚氰胺甲醛树脂（MF）壳的PCM微胶囊。CNF 因其优异的乳化能力、高机械强度和可持续性而被选为 Pickering 乳液的稳定剂和 MF 壳的增强纳米填料。使用石蜡（PW）作为 PCM 材料。所得具有 MF 树脂壳和 PW 核的 PCM 微胶囊的直径范围为 2 至 4 µm。结果表明，核壳比为2（Micro-2.0）的微胶囊表现出最高的结晶潜热和熔化潜热，分别约为128.40 J/g和120.23 J/g。Micro-2.0的封装效率测定为大约79.84%。