Hard carbon and preparation method and application thereof

The invention belongs to the technical field of battery material preparation, and discloses hard carbon and a preparation method and application thereof. The preparation method comprises the following steps: mixing biomass with organic acid, and esterifying at 200-420 DEG C to obtain an esterified material; washing the esterified material with water, and then sintering and pre-carbonizing to obtain a pre-carbonized material; and crushing the pre-carbide material, washing with water, and sintering and carbonizing to obtain the low-impurity and low-pH hard carbon. According to the method, esterification, water washing, pre-carbonization, water washing and carbonization treatment are carried out, and the esterification process is carried out at a specific temperature (200-420 DEG C), so that the finally obtained hard carbon is low in impurity content and low in pH. According to the preparation method, two times of washing are adopted to replace acid pickling, the production cost is saved, and the environmental p